DALLAS (CBSDFW.COM) – The trial began Monday for former Farmers Branch police officer Ken Johnson. He’s on trial for the murder of 16-year-old burglary suspect José Cruz.

State prosecutors started their opening statements just after 10:00 a.m. They admitted to the jury that on the day of the shooting Cruz was “up to no good” and was out stealing. But prosecutors said Johnson put the lives of other teens and members of the public in danger during a car chase and when he opened fire.

Defense attorneys said the allegations are half-truths and that their client is a public servant.

Members of Cruz’ family gathered at the courthouse to pray before the trial got underway.

The case stems back to March of 2016 when Johnson, who was off-duty at the time, saw someone burglarizing a vehicle at an apartment complex. When two suspects, including Cruz, took off at a high rate of speed, Johnson went after them in his own vehicle.

Jose Raul Cruz (credit: Facebook)

After a car chase, that ended at a gas station at Marsh Lane and Spring Valley Road, Johnson fatally shot Cruz, who was 16-year-old, and wounded the passenger in the car.

Johnson is charged with Murder and Aggravated Assault with a Deadly Weapon.

Six men and six women on the jury will decide Johnson’s fate. He has plead not guilty to both charges. The trial is expected to go on for more than a week.