CHICAGO (CBS) — A beloved Chicago man is shot and killed just one block away from the anti-violence center where he worked.

Willie Cooper, a businessman and community activist, dedicated his life to helping others, and now, many are rallying to mourn his death. Sunday afternoon, friends hosted an impromptu vigil to pray for and honor Cooper.

CBS 2’s Dorothy Tucker spent the day learning more about the man, who many affectionately called ‘the mayor of 95th street.’

“It’s heartbreaking. We love him. We will miss him,” said Debbie McBounds. It’s people like McBounds who lined up with others at a makeshift memorial, leaving messages expressing their grief over the murder of Cooper.

“He is just the rock of the family — it just destroyed our family,” said Miltonya Covington, Cooper’s niece. “Not just a loss for family, but also for the community.”

Cooper was gunned down Saturday afternoon near the corner of 95th and LaSalle.

“He would always try to help anyone — the kids who needed to go to college, he gave money for that, anybody who needed help with their rent,” McBounds said.

Among the mourners was Ald. Howard Brookins, who said he was impressed with Cooper’s commitment to rid the community of gangs by providing jobs.

Bamani Obadele, a long time activist, is angry over Cooper’s death. But he said this incident will not give him pause. “It is our responsibility to not allow Willie Cooper’s murder to be in vein,” he said.

Fellow community activists are raising money to offer a reward for any information concerning Cooper’s murder.

Police are still investigating.