A dual U.S.-Mexican citizen who reportedly survived multiple assassination attempts more than a decade ago in Tijuana, and whom authorities said was responsible for importing into San Diego the most concentrated fentanyl ever tested in the region, was sentenced Friday in San Diego federal court to more than eight years in prison.
Aaron Leib Kobisher, 36, pleaded guilty in 2024 to a conspiracy charge involving the distribution of methamphetamine, fentanyl and cocaine. He admitted in his plea agreement that he was involved in a drug-trafficking group based in San Diego and Tijuana that brought the drugs across the border and then distributed them as far as Atlanta and New York.
Spanish authorities arrested Kobisher, alias “El Kobi,” in June 2023 after he had boarded a flight in Madrid that was headed for Mexico City. He quickly waved extradition and within months was brought to San Diego to face charges.
U.S. District Judge James Simmons sentenced Kobisher on Friday to eight years and one month in prison, crediting him for his extensive cooperation with the government, in part by waiving extradition and quickly agreeing to plead guilty.
Kobisher told the judge during the hearing that his involvement in the drug trade had started small but spiraled out of control. He said he was thankful that he was arrested in order for it to stop.
Defense attorney Guadalupe Valencia said that being arrested likely saved his client’s life.
“My client is really remorseful,” Valencia said after the hearing. “He has clearly learned from this whole experience.”
Prosecutors alleged that Kobisher was involved in the trafficking and distribution scheme beginning as early as 2021 and lasting until at least 2023.
One drug seizure linked to Kobisher, made in June 2021, resulted in the discovery of more than four pounds of powder fentanyl, according to Assistant U.S. Attorney Kevin Mokhtari. He said law enforcement agents sent that fentanyl to a San Diego-area Drug Enforcement Administration laboratory to be tested.
Lab technicians soon called the agents wanting to know how and where the drugs were seized because it was the purest, or most concentrated, fentanyl they’d ever tested, Mokhtari told the judge Friday.
As a dual national citizen, Kobisher often crossed between Tijuana and San Diego, but after investigators made several drug seizures linked to Kobisher in October 2022, those crossings suddenly stopped, Mokhtari said. The prosecutor alleged that he had fled to Mexico with no intention of returning to the U.S. until his arrest in Madrid.
According to sentencing documents submitted by Kobisher, he was born in Chula Vista but moved to Tijuana when he was 8 years old. His mother and sister are both dentists in Tijuana, and his brother is an architect.
Kobisher, on the other hand, left home at 16 and began “hanging out with the wrong crowd” and abusing drugs and alcohol, according to his attorney. Despite that, he ended up attending college in Tijuana and settling down with a wife and two children.
“It’s almost like he was living a double life,” Valencia told the judge.
Though Kobisher only pleaded guilty to criminal conduct dating back to 2021, his ties to the criminal underworld appear to stretch back much further.
In 2015, the investigative magazine Zeta Tijuana reported that Kobisher, who owned several Tijuana businesses, had been the target of would-be assassins on at least two occasions. After the first attempt on his life, he hired bodyguards for himself and his family, according to Zeta.
The second reported assassination attempt occurred in April 2015, while Kobisher was riding in a pickup with a chauffeur and a bodyguard, who also happened to be a municipal police officer in Tijuana, according to multiple news reports of the incident. As the trio was driving, another vehicle pulled up and four gunmen opened fire on the truck Kobisher was riding in.
A shootout ensued as the bodyguard fired back at the gunmen, according to Zeta, Tijuanapress and other news reports. Law enforcement authorities later arrested four men they identified as the alleged attackers.