Felon charged with killing girlfriend with gun he allegedly got from legal buyer

A convicted felon from the south suburbs was charged Wednesday with killing his girlfriend with a gun he’s suspected of getting from a man who bought it legally, police and prosecutors said.

Arthur Mendez, 22, is charged with murder in the June 2 slaying of Nicole DeLeon in South Chicago Heights.

DeLeon was found in a bedroom of a home she shared with Mendez, police say.

“The South Chicago Heights Police Department has a history of domestic issues at this address,” Police Chief Bill Joyce said.

Joyce said his detectives “spent countless hours, executed several search warrants, labored over numerous documents, and viewed hours and hours of surveillance video recordings” during their investigation.

Mendez shot the 25-year-old mother twice in the head with a revolver that fired .38-caliber bullets, Cook County prosecutors said during a hearing at the courthouse in Markham.

Prosecutors said the murder weapon could have been a .357-caliber or .38-caliber handgun, both of which can fire .38-caliber bullets.

MORE: Feds charge man with giving handgun to felon who shot young mother

That’s important because Mendez allegedly got the gun from his sister’s boyfriend, who faces a federal charge of illegally providing a .357-caliber handgun to Mendez.

Sabastian Torres, the boyfriend of Mendez’s sister, legally bought a .357-caliber handgun in an online purchase from a store in Minnesota, according to the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives. He picked up the gun at a store in south suburban Monee on May 23, the ATF says.

Torres gave the gun to Mendez about two weeks before the slaying, according to the ATF. Authorities say the .357-caliber handgun that Torres bought matches witnesses’ description of the gun used in DeLeon’s killing. The gun hasn’t been recovered.

Torres was able to buy the .357-caliber handgun legally because he had a state Firearm Owner’s Identification Card, according to federal prosecutors. But he wasn’t allowed to give the weapon to a convicted felon such as Mendez, who was convicted of burglary in Will County, they say.

Mendez was on parole for the burglary when he allegedly killed DeLeon, officials say. He has been returned to prison to serve the remainder of his three-year sentence, records show.

Torres was drinking with Mendez before the killing and dropped him off at his home just minutes before the murder, Cook County prosecutors said Wednesday. Mendez later admitted to his sister and Torres that he killed DeLeon, prosecutors said.

Torres was ordered held without bond last week in federal court on a charge of providing a gun to a felon. He’s been cooperating with the ATF and state authorities investigating DeLeon’s murder, his defense attorney told a federal magistrate judge.

Torres and Mendez belong to the same gang and attended high school together, according to the ATF.