An undocumented immigrant who helped convict a former police officer for sexual assault has been given a second chance following an arrest for drunk driving and near-deportation to Mexico.

"I can't believe I'm back. I didn't sleep for two days and, although what I experienced behind bars was very difficult, I regret what happened and I recognize my mistake. But now I'm going to fight to be someone and capitalize on this chance to the fullest," Abel Moreno told Efe.

The 29-year-old from the southern Mexican town of Tecoanapa said his "nightmare" began on the night of Dec. 29, 2009, when he reported a law-enforcement officer's abusive behavior.

Moreno said at the time his only concern was to help his girlfriend, who was being groped by since-fired Charlotte police officer Marcus Jackson during a traffic stop, and that he was not aware of the consequences his actions would bring.

The immigrant called 911 but was interrupted by Jackson, who then took Moreno into custody for resisting arrest and had him locked up at the Mecklenburg County jail, where the 287(g) "Secure Communities" program identified him as an illegal immigrant.

Days after his arrest, the charges were dropped and Moreno became a key witness in the case against the cop, who had been accused of sexual assault by six different women.

Although he faced possible deportation, Moreno was allowed to apply for a U-visa - granted by the government to immigrants who are victims or witnesses of certain crimes and willing to cooperate with prosecutors.

He was allowed to remain in the country pending the result of his visa application.

The immigrant's testimony helped convict Jackson, who pleaded guilty to sexual assault and received a two-year prison term.

Moreno, says, however, that following that ordeal he suffered from depression and was dismayed at being unable to find a job and send money back to his mother in Mexico. He said those and other problems led him to make the "biggest mistake of his life."

Last Christmas Eve, after having "about four beers" with friends, the Mexican immigrant crashed his vehicle into a tree and a light post.

Police subsequently arrested Moreno on charges of driving while impaired, driving without a license ad fleeing the scene of the accident.

"I didn't flee. I left my vehicle because I was injured. I was really dizzy. The police came and took me to the hospital (and later) back to jail. It was then I knew I wouldn't be able to stay in the United States," he said.

Moreno spent several weeks in the Mecklenburg jail before immigration officials placed him in the Stewart Detention Center in Lumpkin, Georgia, an institution he describes as "horrible."

"But I got advice there from a friend and I appealed against my deportation - since I supposedly signed a voluntary departure (statement) even though that wasn't the case," Moreno says.

After being held for four months, Moreno received word in mid-April that his U-visa had been granted and that he will be able to stay in the country for four years and then apply for permanent residency.

He returned on April 28 to Charlotte and has obtained a work permit and social security card. He is looking for stable employment and trying to put the DWI problems behind him and get a driver's license for the first time.

"I want to obtain my high-school diploma, learn more English and study to be a chef. I love to cook. That's my dream along with bringing my mother here to share a house and getting married," Moreno said.

"But now I know my future depends on my decisions. I'm not going to waste this second chance that life's given me."