LAS VEGAS » A 19-year-old already awaiting trial on murder and other charges in the shooting death of a Las Vegas mother of four is being hit with a separate felony charge alleging that he held a knife to the throat of a 13-year-old boy, authorities said Monday.

Erich Milton Nowsch Jr. faces a battery with a weapon charge alleging that he used a black-handled folding knife to threaten the boy during a Feb. 15 street confrontation witnessed by the boy’s sister and two other girls, according to court documents.

Nowsch hasn’t appeared before a judge on the new complaint, dated Thursday and filed in Las Vegas Justice Court. He is being held without bail at the Clark County jail pending trial May 26 with an accused accomplice, Derrick Andrews, 26.

Nowsch and Andrews have each pleaded not guilty to murder, attempted murder, firing a weapon from a vehicle and conspiracy that could get each life in prison.

Nowsch is accused of firing a .45-caliber handgun from a silver Audi sedan with Andrews at the wheel, fatally wounding Meyers in a cul-de-sac outside her home. Authorities say Tammy Meyers’ son, Brandon Meyers, 22, fired three shots in return, but didn’t hit anything.

Nowsch’s defense attorney, Augustus Claus, said Monday he hadn’t seen the new charge. He declined immediate comment.

Prosecutor David Stanton said police detained and questioned Nowsch during an initial investigation of the knife incident, but didn’t arrest him and didn’t link him at that time to the shootout that left Tammy Meyers mortally wounded.

Meyers died at a hospital on Feb. 14, Valentine’s Day.

Stanton said police interviewed Nowsch on Feb. 15 in the knife investigation.

But at 5-foot-3-inches and 120 pounds with brown eyes, Nowsch didn’t fit the description of a 6-foot man in his 20s with spiky hair and blue or hazel eyes who police were seeking at the time. That person has never been found.

The description and sketch were based on accounts by Meyers’ 15-year-old daughter, who said a motorist in a silver car confronted and threatened her and her mother on their way home from a late-night driving lesson in a school parking lot.

Tammy Meyers dropped her daughter off at home and had Brandon Meyers and his gun with her when the shooting happened. Stanton has said it appears Nowsch fired 24 shots at the Meyerses. Brandon Meyers wasn’t wounded.

Police and Meyers family members first called the death a road-rage slaying.

Stanton now says it appeared to have resulted from a tragic chain of coincidences, including Tammy Meyers’ belief that the silver car with the man in the sketch was the silver Audi driven by Andrews — and Nowsch’s fear that someone was following him.

Nowsch was held at least one night on a warrant in an unspecified juvenile discipline case, then released before his arrest Feb. 19 as an adult in the Meyers slaying case.