An ongoing drug trial in U.S. District Court in El Paso, Texas, provides an uncommon glimpse into the violent battle for Juarez, just across the U.S.-Mexico border. The trial has had as many twists and turns as the Rio Grande, which splits these New Wild West towns into something like Heaven and Hell.

For more than a week in El Paso, witnesses have taken the stand and testified about the world of Mexican drug traffickers. The El Paso Times has reported that their testimony has flashed light on the players and strategies in a vicious turf fight between rival traffickers vying for control of the lucrative smuggling corridor.

The testimony has also skimmed the murkiness of drug enforcement on both sides of the border. At least one witness and even the main defendant have been outed as sources for Immigration and Customs Enforcement who were later arrested by the Drug Enforcement Administration for running drugs.

The testimony comes in the trial of two accused drug smugglers, Fernando Ontiveros-Arámbula, whom an ICE agent today said was an informant for the agency, and Manuel Chávez-Betancourt, who refused to cooperate with the government out of fear for his family’s safety, according to court records. (For safety concerns, the federal judge, David Briones, ordered that jurors have lunch brought in to them each day.) Witnesses have testified that Ontiveros-Aråmbula worked directly under Mexico’s most wanted drug trafficker, Joaquin “El Chapo” Guzman Loera, who leads the Sinaloa drug syndicate, the El Paso Times reports.

The trial has a motley array of characters, from a rooster breeder who stored caches of marijuana in his New Mexico barn to a female trafficker who allegedly survived being shot 15 times to a former Juarez police captain who said all law enforcement in the city and elsewhere in the Mexican state of Chihuahua are on the take, including himself. Among them are several witnesses who have also been indicted or convicted of drug smuggling charges in El Paso and elsewhere and were flipped by the U.S. government to testify against the smugglers.

Among the more intriguing witnesses so far is the former Juarez police captain. Jesus Fierro-Mendez was a 10-year police veteran who ran a counter-narcotics unit, the EPT reports. He left the police department in April 2007 under suspicious circumstances, sources say. Federal agents arrested him at his El Paso home in Oct. 2008. He was sentenced in January to 27 years in prison by a federal judge in Indianapolis.

A quick aside: this former police captain got 324 months for smuggling cocaine into the United States. Most U.S. law enforcement busted for corruption typically get far less prison time. A Pennsylvania Congressman, however, introduced last month a bill that includes stiffer penalties for agents who accept bribes. By comparison, Osiel Cardenas, the notorious former head of the Gulf Cartel, was recently sentenced to 25 years after pleading guilty to drug dealing, money laundering and the attempted murder and assault of federal agents, according to news reports.

The counter-narcotics unit, known as Puma, consisted of young officers fresh out of the police academy who were supposed to be incorruptible, sources say. Little did the rookie cops apparently know that their boss was himself involved in the drug trade.

But Fierro-Mendez’s testimony comes with a twist — he was also an ICE informant who, he said, was authorized by the infamous “El Chapo” of the Sinaloa gang to give U.S. law enforcement information about the rival Juarez cartel.

ICE agents in El Paso have walked down this path before, and not just with today’s news that the defendant was passing information to the U.S. at the same time he was trying to pass loads of drugs. A law enforcement source said it is not uncommon for traffickers to offer information about competitors.

Another ICE informant was implicated in at least a dozen murders in Juarez around 2003. That informant, Guillermo Ramirez-Peyro, known as Lalo, awaits his fate in an immigration detention center in New York.

Last May, a high-ranking member of the Juarez cartel, who was also an ICE informant, was gunned down outside of his El Paso home. Among the hitmen was another member of the Juarez cartel who was also, allegedly, an ICE informant.

After federal prosecutors rested their case today, defense attorney began their questioning. Explosions expected to follow.

Andrew Becker is a reporter for Reveal, covering border, national and homeland security issues, as well as weapons and gun trafficking. He has focused on waste, fraud and abuse – with stories ranging from border corruption to the expanding use of drones and unmanned aerial vehicles, from the militarization of police to the intersection of politics and policy related to immigration, from terrorism to drug trafficking. Becker's reporting has appeared in The Washington Post, the Los Angeles Times, The New York Times, Newsweek/The Daily Beast and on National Public Radio and PBS/FRONTLINE, among others. He received a master's degree in journalism from UC Berkeley. Becker is based in Reveal's Emeryville, California, office.