The gunman remains at large.
Anyone with information should call 215-546-TIPS.
On the afternoon of July 25, Barnes was doing carpentry work at the Raymond Rosen Manor in Northeast Philadelphia.
He went to get tools out of his truck when someone shot him in the head at point blank range.
One theory is that the shooting could be related to a shooting that occurred July 24, a little more than a block away.
Barnes had been working for PHA in the neighborhood every other weekend for about 6 months.
Anyone with any information about the shooting is encouraged to call 215-546-TIPS (8477). Their identity will be confidential.
Funeral services for Barnes will take place this weekend.