Kevin Kelly wasn't even in the United States the day Immigration and Customs Enforcement showed up at his manufacturing facility outside of San Francisco in February, 2011.

"When it happened, I was in Europe looking at printing presses," said Kelly, who took over Emerald Packaging from his father. He recalls rushing home as soon as he heard.

ICE would soon discover that 18 of Kelly's 180 employees had used fake documents to get hired at the factory, which makes plastic bags and other packaging for produce companies such as Dole, Del Monte and Earthbound Farm.

As far as Kelly knew, all his employees were in the U.S. legally. "There are always one or two that you wonder about," he admitted.

But Kelly said everyone had provided Social Security cards and identification, such as driver's licenses and green cards, as proof of their legal status before they were hired. And just as all employers are required to do by law, Emerald Packaging had completed I-9 employment verification forms for each employee.

When the ICE raid happened, the business had also just started using E-Verify -- a federally-run online tool that crosschecks the information on an employee's I-9 form against records maintained by the Social Security Administration, Department of Homeland Security and the State Department.

The ICE agents arrived at the Union City, California, facility on a Monday and requested I-9 forms for all Emerald Packaging's employees to be sent to the agency's local office by the end of the week.

"We sent over boxes of forms to them," said Kelly. After about three weeks, ICE had surfaced the 18 workers, all of whom had worked at Emerald Packaging for at least a decade.

As word of the ICE investigation spread across the factory floor, a dozen workers confessed on their own. Eventually, all 18 were let go.

"Overnight, we lost 10% of our workforce," said Kelly.

Emerald Packaging was never fined "because the agency found that we did nothing wrong," said Kelly. And none of the 18 workers were arrested as a result of the audit, the company's attorney Marcine Seid said. Four of the fired workers eventually gained legal status and Kelly rehired them.

ICE spokesman James Schwab declined to comment on the Emerald Packaging I-9 audit other than to say the agency routinely conducts checks of companies' hiring records to ensure businesses are complying with the law.

Still struggling to replace talent

Six years later, Emerald Packaging is still suffering.

"Productivity fell 15% right after the raid because suddenly we didn't have those people to staff the machines," said Kelly.

The company took an initial financial hit as it doled out extra overtime pay to the workers who picked up the slack.

Hiring was also a problem. "We are willing to hire Americans. I mean, the people who work here obviously are Americans in the same way my grandparents became Americans when they emigrated from Ireland in the 1920s," said Kelly. "But we can't get white people, if you will, to take these jobs."

And when Kelly did find people who wanted to work at the factory, many of them didn't have the same level of skills or the years of experience of the lost workers. Other applicants failed to pass the drug test, said Kelly.

"New hires have come and gone, but we're still in that period six years later where these workers don't have the skills that those [fired] people had. This hurts productivity. There's just no way around it," he said.

While Emerald Packaging has grown -- it has 239 employees today -- there are 17 current job openings on the factory floor that Kelly is struggling to fill. Productivity is still down about 5% today, he said.

Kelly said his company wasn't knowingly hiring undocumented immigrant labor to keep costs down.

"These aren't cheap positions," said Kelly. They range from $15 an hour entry-level jobs to $35 an hour for experienced mechanics. "With overtime of $27 to $35 an hour, you can make pretty good money of $75,000 to over $100,000 a year," he said.

"The people who left were making over $20 an hour, five or six years ago. They were putting their kids through school and college," he said. “When people say these companies are hiring illegal labor because they want to keep their costs down... in our case that argument is complete bullshit."

During the early years of the Obama administration, work site raids ramped up significantly. But in 2014, the administration began focusing more on arresting undocumented immigrants engaged in criminal activities instead.

Now, as President Trump fulfills his tough-on-immigration campaign promises, companies are growing concerned that work site raids may make a comeback, said Jeff Ghouse, a partner with Ansbach & Ghouse, a Dallas-based law group that specializes in immigration issues.

"One of the biggest worries that our clients have is that a government official with a gun and a badge will show up in their lobby asking questions," Ghouse said. "This has the potential to disrupt business opportunities with customers that may be visiting the client that day, as well as cause concerns with existing employees."

Losing Miguel

Kelly said the workers he lost as a result of the ICE raid were some of his most experienced employees.

"We lost tremendous talent. And to this day, we haven't been able to replace it," said Kelly.

Losing Miguel Gonzalez stung the most, he said.

Gonzalez had worked for Emerald Packaging for over 20 years. He started as a box handler, moving and storing product pallets and factory supplies, and worked his way up to assistant foreman. He was a gifted mechanic and Kelly relied on him to help keep the factory running.

"You not only end up losing a person who knew how to work the machines really well, you lose a person who could walk into my office and tell me what's going on in the facility," he said.

Keen to learn and move up the ranks, Gonzalez routinely took on extra work and hours. He also rarely missed work, even returning to the factory floor just two days after his first child, Casandra, was born.

"Losing him had an immediate impact on production because there just wasn't anybody of Miguel's caliber to replace him. There just wasn't," said Kelly.

When Gonzalez was flagged as one of the 18 undocumented workers, Kelly's heart sank.

"I was very upset to see Miguel go, but I had to," said Kelly.

"If Miguel came back to work at the company, he could have been charged with using false documents to deceive the U.S. government and receive U.S. benefits," said Helen Ramirez, an immigration attorney with Ramirez & Ramirez.

Neither could he have used the same fraudulent documents to obtain another job. "The system used by his new employer to verify employee eligibility to work would have flagged him," she said.

So about five months after the ICE raid, Miguel moved his family to Mexico.

"Miguel was tired of driving down the street, worried about whether he was going to get pulled over by a police officer, checked and arrested," said Kelly. "So he just finally had had it and left. He went home."

"I knew sooner or later I could get caught," said Miguel Gonzalez.

In February 2011, Immigration and Customs Enforcement officials showed up unannounced at Emerald Packaging, the factory where Miguel worked.

As a result of the raid, 18 of the Union City, California factory's 180 workers were caught using fraudulent and counterfeit documents, such as Social Security cards and green cards, to establish their legal status and land jobs.

Miguel was one of them. He was called into the human resources office a few days later and let go.

"That day broke all my dream," said Miguel.

Miguel had been working at Emerald, a manufacturer of plastic bags and other packaging products for fresh produce companies, for more than 20 years.

When he was fired, he was making $22 an hour and getting retirement and health benefits. Miguel paid taxes. He had a house in the suburbs, he owned a car and he was putting money away for his three kids to go to college.

"My life was like any American family," said Miguel, who is now 48. "My kids played baseball, soccer. We took vacations, I was paying my mortgage and saving money to pay for college."

While Emerald's attorneys were able to help four of the workers gain legal status, Miguel gave up on finding a way to keep his job or stay in the country.

"The day [they] let me go, [it] broke my heart," he said. "In my mind came a lot of things. All the time I worked for them. All the things I did for them. All the years I worked really hard. That day changed everything."

Throughout his time in America, Miguel had never been arrested. Now he was scared he was on ICE's radar. He could be tracked down and potentially deported. It terrified him to think he'd be separated from his children if he and his wife, who was also an undocumented immigrant from Mexico, were deported.

"I really wanted to stay in the United States, but something in me was broken. My American Dream was broken," he said.

Miguel found another factory job in the area, but his heart wasn't in it. "I felt it was time to go back to my country and start over," he said.

About four months after the raid, in June 2011, Miguel moved his entire family back to his hometown of Tala, outside of Guadalajara, Mexico.

His children, ages 6, 11 and 13 at the time, had all been born in the United States -- making them American citizens.

"If this had happened to me a few years later, at least my oldest daughter and my son would have been in college, making their own lives," he said. Now, back in Mexico, the future was much more uncertain.

A dream deferred

The last time Miguel had lived in Mexico, he was a 19-year-old auto mechanic looking for more out of life.

"I had bigger dreams for myself," he said. In 1988, he paid a coyote -- a person who smuggles people over the border -- $200 to help him enter into the U.S.

After he crossed the border near Tijuana, he made his way to Oakland, California, where a cousin took him in. At the time, Miguel didn't speak English.

His first job was grueling. "I poured concrete in backyards. I worked from 6 a.m. to 6 p.m. for $50 a day and no breaks," he said.

But then he got a driver's license from the Department of Motor Vehicles in Oakland. Prior to 1994, the agency didn't require applicants to show documents of "legal presence" in the U.S. So the only thing Miguel had to show was his Mexican birth certificate.

A driver's license was the key that opened the door to "a regular American life," he said. "With that ID, I bought a car and rented an apartment," he said.

He also bought a fake Social Security card and green card (paying $100 for each). "We had ways to get the documents we needed," he said.

Miguel knew this was illegal, "but this was the only way I could get a job," he said.

He soon managed to upgrade jobs, becoming a janitor at a local JC Penney where he worked for two years. As the years passed, he said he even forgot that most of his documents were fraudulent.

In 1991, a friend told him about job openings at Emerald Packaging. The possibility of working with machines excited Miguel. But he needed to pass a company English test first. Luckily, he had been taking English lessons at a local school in Oakland for almost two years.

"They gave me 100 questions to do in 30 minutes. I finished in seven minutes, almost all correct," he said.

Miguel landed the job at Emerald, and started out earning $7.97 an hour moving and storing pallets. But he showed initiative by tinkering with and fixing up the machines on the factory floor on his own time to help them operate better. Two years into the job, he was promoted into a role where he learned to set up, repair and maintain the factory equipment.

Kevin Kelly, his boss at the time, remembers Miguel as one of his best workers. "He was the single best machine mechanic we had."

Over time, Miguel taught himself every aspect of the business, including payments and shipping. Two decades after starting at Emerald, he was a foreman making $22 an hour.

As he settled into his blue-collar American life, Miguel made a few trips back to Mexico by car to visit his family. His driver's license easily got him back across the border, he said.

During one visit in 1994, he met his wife Maria and married her. A few years later, Maria, too, came into the U.S. with the help of a coyote. First, the couple rented a house in Hayward, California, a suburb close to Emerald's factory.

Their first child, Casandra, was born in 1998 and son Miguel Jr. soon followed in 2000, later came Alexandra. Miguel was worried the schools weren't good enough in Hayward so he moved the family to the suburb of Tracy. The schools were better, but it meant Miguel would commute a total of three hours every day to and from work.

Miguel was closer than ever to attaining the American Dream. But the closer he got, the more fearful he became about losing everything: the job, the house, the car, sending his kids to college in America.

When ICE arrived at Emerald and discovered Miguel's status, he hit a breaking point. "The raid affected me too much," he said.

Of the 18 undocumented workers at Emerald outed by ICE, Miguel was the only one to decide to leave the U.S.

'It's taken us many years to feel better'

When the Gonzalez family first arrived in Tala, Mexico, it was a tough adjustment.

All three children were sent to schools where classes were taught in Spanish -- a language they didn't know.

The move was hardest on Casandra, who was 13 at the time. "Moving to Mexico was heartbreaking for me. I was desperate to go back [to the U.S.]," she said.

Miguel picked up the reins at his father's business, Bloquera San Miguel, which makes concrete construction bricks. "When I came back, the business was in trouble," he said.

His father, Camilo, tried to manage everything, but Miguel learned that workers had been stealing money and he had to fire all of them.

Miguel now runs the operation. His 17-year-old son and his friend help him manage the daily work. Any profits go directly back into the business. But things are picking up.

"I want to take out a loan to buy better machines and hire more workers," Miguel said.

Six years after leaving the U.S., Miguel admits that the move to Mexico has been a struggle. He said he's been extorted several times by a local drug cartel, losing half of the $35,000 in savings he brought back with him. He's even witnessed a gunfight outside of his home.

His wife and daughters bring in extra cash by working at his sister's restaurant on the weekends.

But they're learning to adjust. His youngest daughter now speaks Spanish so well she doesn't speak English and his oldest son and daughter are more fluent in Spanish.

"We always think about America," said Miguel. "We had a good life there. It's taken all of us many years to feel better."

It's been six years and Casandra Gonzalez still feels caught between two worlds.

When she recalls how her family abruptly fled the United States, the feeling is so palpable it reduces her to tears.

"I will never forget how extremely hard it was for me and my family after we left America and came to Mexico," said Casandra, who is now 19.

Casandra's father, Miguel, moved the family to Tala, Mexico in 2011 after Immigration and Customs Enforcement agents showed up at the factory where he worked.

The ICE agents discovered 18 of the company's 180 workers had used fraudulent and counterfeit documents, such as Social Security cards and driver's licenses, in order to secure their jobs.

Casandra's father was one of them. He had a legal U.S. driver's license, but all the rest of his papers were fake.

He had been working at Emerald Packaging for more than 20 years. In that time, he had built a life for himself, his wife and three U.S.-born children, Casandra, Miguel Jr. and Alexandra, in the middle-class suburb of Tracy, California.

Casandra was 13 when her father lost his job that day. A gifted student, she was about to start high school and dreamed of going to a good American college.