Mercado says that changed the murderer's mind. "Somehow he escaped from jail. He returned back to the L.A. area. He turned himself in. He said he didn't like the prison over there. He said he really was a U.S. citizen. So they prosecuted him over here in West Covina and sentenced him to 44 years to life in state prison."
But usually it's a long formal process. "First, after arriving at the airport and checking into a hotel, we'll meet with the chief federal prosecutor in that state," says Mercado, "and he will assign a federal attorney to take up the [issue] with us. In each case we will take down an English file and a Spanish file. We'll have four copies of each required by their legal system. We will sit there, and the attorney will go over it, review the case, review any questions. They're required by law to deal with it. Mexican federal penal code, article 4, gives authorization [for us to] file these cases."
The problem is, U.S. prosecutors must file their warrants through Mexico's federal police, even though it is the state judicial police whose job it is to chase felons. To get around this, Mercado often pays a discreet visit to the state police to let them know who he's looking for, after handing over his files to the federal authorities.
But the biggest problem is the neighbors' differing legal systems themselves. While the U.S. system is based on English common law, the Mexican law derives from Napoleonic and Roman law.
According to Juan Jose Briones, the result is that criminal procedures are completely different in California than in Mexico. Briones, a close colleague of Mercado's, is international case coordinator for the San Diego County DA's office. "In Mexico, the prosecutors are also the investigators, with the assistance of the [state] judicial police. Whereas in the U.S., the prosecutors have nothing to do with the investigation itself. The police departments do the investigation, and the prosecutors do the prosecution.
"In Mexico the prosecutors do both. They investigate and they prosecute. Because of historic reasons, they are doing away with the police investigation and getting the prosecutors involved more in the investigation."
This apparent lack of trust among Mexican authorities for their police is now affecting the evidence that Mercado and Briones take to Mexico. "Until recently the elements in a Mexican investigation were basically the same as in a U.S. investigation: we would give them police reports, witness statements, autopsy reports, death certificate, and we got convictions.
"But recently some Mexican judges are releasing persons who are already in custody, because they say the [American police] reports constitute [only] hearsay. They say, 'We need you to go and interview the witnesses again, have [witnesses] give a statement directly, instead of through a [police] officer, and have them sign at the end of their statement, as we do in Mexico.' "
"I think the reason behind it is that they do not have a [live, jury] trial in which the witnesses will have an opportunity to say the same thing again. So they want to get it 'straight from the horse's mouth' the first time, and with his signature because that way you can say, 'You read this and you signed it.'"
But Briones says he and Mercado do not accept Mexico's dismissal of U.S. police reports. "We feel that the [Mexican] judges are wrong, and we can prove that they're wrong. In international law, you cannot request a country to apply your laws [to its investigation]. How would we like it if Japan gave us the Japanese code and said, 'Do your investigations this way'?"
"Listen, sir. You do whatever you want, but I'm advising you: don't file the case the way it is. Don't do it."
Enrique Mercado is talking to his other big problem. A renegade police department somewhere in California that wants to go chase their felon in Mexico independently.
"I won't give you that particular police department's name," Mercado says to me. "I think they've learned their lesson, but apparently they sent two detectives who went and met with some Mexicans in Mexico City. They sent me the case to review it and have it translated. But when I looked at it I said, 'No, this is not acceptable. The case you bring to us to file in Mexico has to be prosecutable here. We're not going to file cases [over there] just so you can close them [here].' They do that! But this PD filed it anyway. And, naturally, the Mexicans kicked it back to them. They still have it."
What does get results in Mexico, say Briones and Mercado, is attitude. "We always try not to be pushy, not to be seen as coming down to tell Mexican authorities what to do. Because they do resent that," says Briones.
"We go all over," says Mercado. "Oaxaca. Jalisco. Veracruz. But we don't say, 'Here's the case, we want you to do this...' No. 'We request your assistance....' It's the way you present yourself. We go with respect, because it is their laws, their country."