The 30-year-old officer, named only as Eduardo N., was killed on Wednesday in the city of Culiacan, Sinaloa.
"It's insane to think that Guzman would have all that money," one of "El Chapo" Guzman's attorneys said.
The notorious drug kingpin has previously escaped from two Mexican prisons.
"I wouldn't put it passed the two sons to start targeting the people who put their father away for life."
The U.S. Government is reportedly seeking over $14 billion in drug proceeds and illicit profits from Joaquin "El Chapo" Guzman as part of his criminal proceedings.
"He still has capability and resources while his kids run his business for him," Derek Maltz, former Special Operations head of the Drug Enforcement Agency, told Newsweek.
One of the drug lord's pilots testified that he saw Joaquín "El Chapo" Guzmán kill three members of rival Mexican cartels sometime around 2007.
Former cartel members testified that narcotics were hidden in shipping containers, passenger cars with hidden compartments, trucks, tanker trains and even cans of jalapeños.
Lucero Guadalupe Sanchez Lopez described a difficult relationship with the Mexican drug cartel boss.
Pena Nieto dismissed the allegations as "false and defamatory."
Watch: The Texas senator shows how the El Chapo Act would fully fund the wall proposed by President Donald Trump.
Vicente Zambada Niebla gave more than five hours of testimony about the operations of the Sinaloa Cartel, for which he had been groomed as a future leader.
Juan Carlos Ramirez led the Colombian North Valley cartel and sold cocaine to El Chapo.
The DEA confiscated a shipment of canned jalapenos in Tijuana, Mexico, from a counterfeit company called La Comadre, according to a witness.
Jesús "El Rey" Zambada, former member of the Sinaloa cartel, is singing like a canary.
Emma Coronel Aispuro, 29, has attracted media attention because of her lavish lifestyle in Mexico.
Given the reputation of "El Chapo" as a dangerous individual, jurors will remain anonymous.
"There is no doubt that the defendant and his cartel have the capability, the resources and the will to harm cooperating witnesses and their families, even after they have been relocated," Federal Judge Brian Cogan has warned.
Miguel Angel Corea Diaz, 35, known as "Reaper," complained about not being able to use his phone in jail and death threats.
Despite formerly serving under Guzmán, López aimed to take control of the Sinaloa cartel and launched a bloody feud with El Chapo's son for control in 2016, according to reports.
The Justice Department charged CEO Vincent Ramos and his associates of racketeering and conspiracy to facilitate drug distribution.
Prosecutors have requested a partially sequestered jury in Guzmán's trial.