FORT WORTH — A trial started Monday that could lay bare the sophistication and brutality of Mexican drug cartels that reach into even the most affluent North Texas suburbs.

Security was exceptionally tight for jury selection at the U.S. Courthouse in Fort Worth. Two men are charged with interstate stalking and conspiracy to commit murder for the death of Juan Jesus Guerrero Chapa.

Many Federal officers patrolled inside and out. Acting U.S. Marshal Rick Taylor was also on hand. No cameras or even cellphones are ever allowed inside the courthouse.

Judge Terry Means told potential jurors that for their protection, he would keep their names secret even from lawyers. An unnerving start to the trial of two men accused of tracking a drug cartel lawyer so hit men could murder him.

Chapa died in a barrage of bullets while shopping with his wife at Southlake Town Square in May of 2013. A defense attorney described him as the defacto head of the Gulf Cartel.

According to court documents, Jesus Gerardo Ledezma-Cepeda and his cousin, Jose’ Luis Cepeda-Cortes, used GPS tracking devices and surveillance cameras to set the trap. The two middle-aged men wore ties and sport coats in court. After bailiffs removed handcuffs, the defendants looked like any members of court staff as they faced a pool of 60 possible jurors.

A son of one of the defendants, who was also arrested, will testify for the government. Federal prosecutors plan to call about 30 witnesses, including top FBI experts on computer forensics and cyber crimes.

Defense attorneys want to call the former leader of the Gulf Cartel. Osiel Cardenas Guillen is in US federal prison after cutting a plea deal. It’s not clear whether he will testify.

The trial in Fort Worth could take a month. Several potential jurors told the judge that would be hard for them to do. Opening statements and testimony are scheduled to begin Tuesday.