Two brothers were charged with murder in the death of a police officer gunned down during a robbery at a video game store, where the officer had gone to buy a present for his 9-year-old son for getting good grades, police said.

One brother, 29, was on parole for robbery, and the other, 24, also had a prior arrest, Police Commissioner Charles Ramsey said. They were to be identified at a late morning news conference Friday to discuss the fatal shooting of Officer Robert Wilson III, 30.

Also Friday, sentencing was being held for a man convicted in the last killing of a city police officer 2 1/2 years ago.

Wilson was in a north Philadelphia GameStop late Thursday afternoon when the two suspects entered and announced a robbery, Ramsey said.

Wilson, a father of two on the force eight years, was shot multiple times but was able to wound one of the suspects. His partner also exchanged gunfire with the suspects, but was not shot.

The police commissioner said he met Wilson and his partner when they took part in a recent pilot program in which officers wore body cameras. It was not immediately clear if Wilson was wearing a body camera when he was shot, but authorities did seize video from store security cameras.

Another weapon, which police described as an AK-47, was recovered during a search at one of the suspects' home, Ramsey said.

"It's a tremendous loss in so many ways," Ramsey said. "Our focus now is really trying to get the family through it -- particularly his son. It's just a tough time for everybody. How do you explain it?"

A police procession escorted an ambulance that transported Wilson's body Thursday night.

The last city officer killed, Moses Walker Jr., 40, was shot in an attempted robbery as he walked to a bus stop after an overnight shift in August 2012. His killer was convicted of first-degree murder in December in a nonjury trial that spared a possible death sentence.