Image copyright Family Handout Image caption Jordan Edwards was described as a standout student and athlete

A former police officer who shot an unarmed black teenager in the head has been indicted on a murder charge by a grand jury, prosecutors in the US state of Texas say.

Roy Oliver, 37, fired a rifle into a car that was driving away from a party in the Dallas suburb of Balch Springs in April, killing Jordan Edwards, 15.

His lawyer has not commented. No date has been set for the trial.

The policeman was sacked a few days later for policy violations.

The death occurred when police responded to reports of underage drinking at a house party.

Officers were inside the home trying to find the owner when they heard outside what they believed to be gunshots. Roy Oliver fired into a car full of teenagers as they left the party.

Police had initially said the vehicle reversed "aggressively" towards the officer, but footage discredited the claim, showing the car driving forward, away from him.

He was also charged with four counts of aggravated assault with a deadly weapon by a public official, in relation to the other four teenagers, including two of the victim's brothers, who were in the car.

Image copyright Reuters Image caption Roy Oliver opened fire with a rifle, killing the teenager

"It is important to let our community know that justice is proceeding effectively and thoroughly at the Dallas County DA's office," Faith Johnson, the county's district attorney, said in a statement.

The teenager was described by his coach as "a checklist of everything you would want in a player, a son, a teammate, a friend".

Roy Oliver faces five to 99 years in prison on the murder charge, the Dallas Observer reports.

If convicted, he would be the first police officer convicted of murder in Dallas county since 1973, the report adds. He is currently free on bail.

Lee Merritt, a lawyer for the Edwards family, said on Twitter: "We remain cautious. A murder indictment for Roy Oliver is appropriate but the fact is it's been [more than] 40 years since a cop was convicted in [Texas]."