Propped up on each arm by family, Shirley Barnes walked to a podium that stood just blocks from where her husband, Rodney, was critically injured in a shooting that might have been a case of mistaken identity.

"We are praying for you," she said of the person who shot her husband, a carpenter for the Philadelphia Housing Authority and a minister at the Mount Airy Church of God in Christ.

"To the young man or woman who did this to my husband . . . you can turn your life around. You don't have to live this way."

At a news conference yesterday, the PHA and Barnes' union, the Metropolitan Regional Council of Carpenters, announced a joint $10,000 reward for information leading to the arrest of Barnes' killer.

The shooting "is just something I don't think anyone wants to put up with or wants to tolerate," said John Appledorn, president of the Citizens Crime Commission of Delaware Valley, which is administering the reward.

Barnes, 46, of Elkins Park, was shot in the head Saturday afternoon while working at the Raymond Rosen Manor housing project, 24th and Norris streets, in North Philadelphia.

He was unloading his tools into a red truck when an unknown person drove up and fired a single shot at Barnes before driving away.

The motive remains unclear. Investigators are trying to determine if the shooting was a case of mistaken identity, police sources said.

A red truck - similar to the one Barnes was loading - was involved in a neighborhood shooting on Friday, the sources noted.

Shirley Barnes said that her husband was "holding his own" as he fought for life in Temple University Hospital, where, police said, he is listed in critical condition.

Barnes runs his church's prison ministry, said Bishop Ernest Morris Sr., the founder of the Mt. Airy Church of God in Christ, and described Barnes as "calm and likable."

PHA director Carl Greene said that Barnes was serving the public when he was shot on the job.

"He was putting the interests of supporting his family and the interests of the poor ahead of anything else he could have been doing on a Saturday," Greene said.

Anyone with information about the crime should contact the Crime Commission at 215-546- 8477.