That he is still in the United States, now charged with murder in the traffic death of Kent Boone, an Antioch resident, is inexplicable to Boone's family. Law enforcement authorities can't explain it either.
"It's been quite challenging getting any information on anything," said April Godin, Boone's former wife and the mother of two of his five children. "It's just all of the loopholes and lack of information," she said, which compounds their pain.
Pena pleaded not guilty to second-degree murder in court Wednesday.
"To sit there and see him staring forward" in the courtroom was difficult, Godin said after Pena's court appearance, which lasted about 10 minutes.
Pena was hospitalized for a week after the March 31 crash on Highway 12 and then jailed in Solano County. Prosecutors say he was under the influence of alcohol and drugs, without a license and in possession of 2 pounds of methamphetamine when the Ford SUV he was driving slammed into Boone's pickup, killing him.
For unexplained reasons, Pena was below the radar of anyone who could have stopped him before the accident. He had walked out of jail more than once.
Pena, who has used at least three other names, has been arrested or convicted at least nine times dating to 2003, including three for drunken driving, according to the state Department of Motor Vehicles and the Solano County District Attorney's Office.
The fatal accident came on the two-year anniversary of the Department of Motor Vehicles' notifying Pena by mail that his license was suspended for DUI, according to DMV records. It's not clear why those same records indicate that he had no license and possibly never has, at least under that name.
He has been convicted six times of driving without a license.
Pena was convicted twice for DUI in Contra Costa County, in 2003 and 2005, and for a felony narcotics count in Contra Costa in 2005, according to the DMV and the Solano County District Attorney's Office. He was convicted of DUI in Solano County in 2005.
Records do not show the circumstances of his release. Many people arrested for misdemeanor DUI are released with a citation after a short time in jail.
Local police agencies and the Contra Costa Sheriff's Office, which runs the County Jail, typically do not stop and arrest people solely on suspicion of their immigration status. But they will investigate if an arrestee has been charged with a serious crime.
"If you're a criminal, we're going to use any tool possible to make your life miserable," including immigration status, said San Pablo police Cmdr. Mark Foisie.
"It's appropriate if you're dealing with a violent felony or a crime of moral turpitude," Foisie said. "It's something that would be followed up in an investigation, not something that is asked in the field."
When Contra Costa sheriff's deputies arrest someone, "an immigration status is only incidental to the crime the person is arrested for," said sheriff's spokesman Jimmy Lee. "Whether at the jail or in the field, it may be discovered that an individual has an immigration hold. In that case we will notify" the federal Immigration and Customs Enforcement Agency, he said.
ICE personnel routinely visit County Jail in Martinez to check the immigration status of arrestees there, as well as in other major metropolitan areas.
The California Highway Patrol checked and determined that Pena was an illegal immigrant during the investigation of the March 31 accident because officers could not verify he had a valid identification, said Solano County CHP spokesman Marvin Williford.
An ICE spokeswoman said no one ever told the agency about Pena.
"Cases like this certainly underscore why we want to encourage local law enforcement agencies to tell us when they encounter foreign nationals with multiple prior convictions for crimes that certainly present a potential threat to public safety," said Virginia Kice, a spokeswoman for the federal Immigration and Customs Enforcement agency.
ICE has placed an immigration hold on Pena, who is being held without bail at the Solano County Jail. That document is a request that Pena be turned over to immigration authorities if and when he is released from jail, Kice said. If he is convicted, he could be deported after he completes his sentence.
Police departments that confront large immigrant populations say they have worked to build credibility with them and have responded to any perception that they target people because of their immigration status.
"The only time it's a relevant issue is if someone is charged with a crime and we incarcerate them," said Concord police Lt. David Chilimidos.
"We actually treat everybody like they were here legally," said Richmond police Capt. Alec Griffin. "We don't make contacts with ICE just in the course of normal business."
Richmond police have not participated in ICE roundups of suspected illegal immigrants and have stopped daylight traffic checkpoints aimed at street criminals -- because immigrants feared they were the targets, Griffin said.
How Pena remained free despite multiple journeys through the legal system, including in Contra Costa and Solano counties, remains a mystery. The lack of an apparent reason has been more difficult for Boone's family to accept.
"It doesn't seem like it would be hard to put a red flag on there," Godin said. "There's so many questions I have. ... Why isn't anyone giving us information?"
Reach Scott Marshall at 925-945-4782 or firstname.lastname@example.org.
how to help
A trust fund has been established to help the family of Kent Boone at Wells Fargo Bank, 3365 Deer Valley Road, Antioch, CA 94591. The account number is 9968017716.