McALLEN — Former lawman and Hidalgo County constable candidate Robert “Bobby” Maldonado, accused by authorities of running cash loads for Mexican drug cartels, pleaded guilty Monday morning to money laundering charges.

Maldonado, who was running for Precinct 1 constable at the time of his February 2012 arrest in Victoria County, spent about 12 years working as a courier bringing drug proceeds back to the Texas-Mexico border from the U.S. interior, according to prosecutors.

Maldonado was the target of a lengthy federal investigation for his alleged dealings with a Mexican drug cartel, from which some of the money was funneled into his unsuccessful bid for constable and into other pachangas, according to Monitor archives.

Assistant U.S. Attorney Henry Sturgis said Monday that Maldonado, 49, would buy one-way flights to cities including Detroit, Chicago and Birmingham, Alabama, rent cars and drive the money back. He generally received about 3 percent of the money he carried as payment and invested it in properties and other assets disguised under other names, Sturgis said.

The period during which Maldonado did this came after his 1995 firing by the Texas Department of Public Safety, but did overlap with the several years he spent at the Hidalgo County Sheriff’s Office, including under former Sheriff Lupe Treviño, who has pleaded guilty to money laundering in a separate case.

The extent to which Maldonado used specific skills acquired in law enforcement to evade detection could lead to an enhanced sentence, U.S. District Judge Randy Crane warned Monday.

Maldonado’s plea came a week before his trial was scheduled to begin.

Maldonado’s 2012 arrest came when a state trooper pulled him over along U.S. Highway 59 near Victoria and a police dog led the trooper to the trunk of his Chrysler 200 sedan. Inside, authorities found and seized $1,068,930 in cash bundles.

Soon after his arrest, federal agents raided his lakeside mansion north of Mercedes. At the home authorities found various exotic animals, including bison, kangaroos and snakes.

During Monday’s hearing, Crane accepted Maldonado’s guilty plea and set his sentencing hearing for July 21, at which time he could face a prison term of up to 20 years and a $500,000 fine, the U.S. Attorney’s Office said in a prepared statement.

Federal agents had followed Maldonado to South Carolina, where he was suspected of picking up the money, but they lost track of him near Houston, according to Monitor archives. The agents asked for help from other agencies, leading to the traffic stop.

Maldonado was terminated from the Texas Department of Public Safety in 1994 after allegations that he pointed a handgun at a man who was with his estranged wife.

The charges were later dismissed and his peace officer’s license was not suspended, allowing him to still work as a lawman.