The arsonist in the massive parking garage fire at Kings Plaza last September pleaded guilty in federal court Wednesday.

The fate of 23-year-old Evon Stephens is now in the hands of a federal judge.

Stephens pleaded guilty in federal court, telling a judge exactly what he did last year in the Kings Plaza shopping mall.

Cameras were not allowed in the courtroom, but when the judge asked Stephens what he did in September of last year, he said, "I lit a car on fire with matches."

He then confirmed the fire spread, causing several vehicles and other property in the parking garage to be severely damaged.

A law enforcement source told News 12 last year that federal charges were brought because the cars were from dealerships, which involved interstate commerce.

At the time of the incident, prosecutors say Stephens confessed to starting the fire because he believed people were having sex in the parked cars.

In court, the judge questioned Stephens about his mental health history.

Defense attorneys say Stephens does have a history of psychiatric hospitalizations, but they were not recent and that an evaluation by a professional has them not concerned about his competence.

Earlier, Stephens signed a plea agreement with the government and he told the judge he understands that means he will be serving a minimum of five years in prison.

He's expected to be sentenced on Aug. 20.