DALLAS (CBSDFW.COM) – Former Farmers Branch police officer Ken Johnson was found guilty of murder Tuesday in the death of a teenager.

Ken Johnson (credit: Addison Police Department)

He was also found guilty of aggravated assault in March incident that left 16-year-old Jose Cruz dead and his friend seriously injured.

Jose Raul Cruz (credit: Facebook)

Johnson opened fire after catching teens stealing seats from his SUV.

Sentencing is scheduled for January 8, 2018.

It was on March 13 when investigators say Johnson, who was off-duty at the time, saw someone burglarizing a vehicle at a nearby apartment complex. When suspects Jose Cruz and Edgar Rodriguez Arevalo sped off, Johnson went after them in his own vehicle.

After a car chase that ended at a gas station, Johnson fatally shot Cruz, 16, and wounded his friend Rodriguez.

In a later interview Rodriguez said Johnson did not identify himself as a police officer until after the shooting. Johnson’s attorney says his client did so repeatedly, saying, “Police, show me your hands.”

After being charged, Johnson resigned from the police department. It was just days after stepping down from the police force that Cruz’ family filed a wrongful death lawsuit against Johnson and the City of Farmers Branch.