He was on probation and wearing a GPS monitoring device. He was also armed with a rusty machete, and prosecutors said he carjacked a woman as she checked the oil in her car on Ravenwood Avenue in May.

On Tuesday, a Baltimore Circuit Court jury convicted the teenager, Terrell Singleton, of carjacking and car theft, and he faces up to 69 years in prison when he is sentenced in April. Prosecutors said the GPS device he was wearing, so that prison officials could keep track of him, put him at the scene of the holdup.

The Baltimore State's Attorney's Office said that the woman was attacked on May 24. She saw two men approach and got into her car, "but one of the men reached in and brandished a 17-inch machete, stating, 'This is a jacking, hurry up.'"

Prosecutors said the woman got out and the men got in, driving off and throwing a purse out the back window. Baltimore County police stopped the car four hours later after a chase, and prosecutors said Singleton was arrested after he forced his way into a home, dropping the machete in the yard.

Electronic court records show that Singleton had been convicted previously as an adult with assault and given a 10 year sentence starting in August last year, with all but nine years and 10 months suspended. He was put on four years supervised probation.

That case stems from an incident in which another man, just last week, was convicted of trying to kill Singleton by shooting him out of revenge for the assault. Dafton Canty was found guilty of trying to shoot Singleton. Canty missed, but hit and wounded a 10-year-old boy instead.