Geovani Hernandez, 43, formerly a sergeant with the Progreso Police Department, was charged with three federal offenses in an investigation dubbed Operation Blue Shame
and placed in jail under a $100,000 bond.
Hernandez was charged with attempt to possess with intent to distribute a controlled substance, possession with intent to distribute more than 5 kilograms of cocaine and aiding and abetting.
In a hearing Friday, a federal magistrate found probable cause to try Hernandez.
CNN has reached out to a lawyer listed in court records as representing the ex-officer.
In May, an informant met with Hernandez to discuss an "illegal business venture," at which time the officer claimed to be friends with a "plaza boss" in the Gulf Cartel in Mexico, according to a criminal complaint filed in US District Court in McAllen.
Hernandez said "he needed money for his campaign for Hidalgo County constable," the document says.
In Texas, a constable is a licensed peace officer who performs law enforcement functions, including issuing traffic citations and serving civil papers, such as subpoenas, according to the Texas Association of Counties.
Hernandez has sought political office unsuccessfully before and portrayed himself as an enemy of Mexican drug cartels.
In 2012, he ran for sheriff in Hidalgo County, which borders Mexico, and pledged to battle drug smugglers, the Rio Grande Guardian reported.
"We need to protect our families," Hernandez said during a debate with his opponent, according to the newspaper. "What happens here affects the rest of the United States of America. I have worked terrorism, I have worked borders before. I do not protect drug dealers."
He lost that election but ran again in 2014
as a write-in candidate, and lost again.
Hernandez has worked for several law enforcement agencies in south Texas since the mid-1990s: jailer with the Hidalgo Sheriff's Office, police chief in the town of La Joya and, most recently, sergeant with the Progreso police, CNN affiliate KRGV
reported. He no longer works for that department.
Hernandez recently played a uniformed law enforcement officer in a music video about cocaine smuggling, according to The Monitor newspaper
. The video tells how 6,000 kilos was moved through a border checkpoint.
Federal agents became interested in Hernandez when an informant told them in August 2016 the officer was involved with a drug trafficking organization, the criminal complaint said.
In June, the informant asked Hernandez to run record checks on some vehicles, which he did for $1,000, and later in the month paid him $2,000 to run a records check on a person to see if he was an informant, authorities said.
The informant met Hernandez again July 11 and offered to pay $5,000 for help in moving "items" from a Progreso warehouse to the town of Pharr, the complaint says.
Hernandez told the informant "not to tell him what the vehicle would be transporting, not to discuss any details on their current cell phones and to buy new cell phones," the complaint says.
Agents said the deal went down July 15 after phone calls and meetings with Hernandez. Ten bricks of a white, powdery substance were loaded into a vehicle, along with one brick containing real cocaine, the complaint says.
When the informant and the officer met that day, Hernandez told the informant to get into his private vehicle and listened as the informant put a phone on speaker mode so Hernandez could hear the conversation, in which the person on the other end discussed their movements, the complaint said. Hernandez told the informant to let the person know "they would be patrolling the streets," the complaint says.
Later that day, the informant met Hernandez and paid him $5,000, agents said.