SOUTHWEST PHILADELPHIA (WPVI) --Frank Halbherr knew Mark Marshall through their union, District Council 33 - Local 1637.
"He was a decent guy. A good, hard working guy," said Halbherr, AFSCME District Council President. "He was in the process of becoming a police officer because he wanted to serve the community that he was killed in."
Marshall was out walking his dogs around 7:45 p.m. on Dec. 16, 2015, along the 4600 block of Kingsessing Avenue in Southwest Philadelphia.
"My understanding is a guy came up, he had words," said Halbherr.
Police say the suspect followed Marshall to 47th and Kingsessing and shot him multiple times.
Marshall died at the hospital.
"Today there is no fistfight, and it's pulling a gun and it's over," said Halbherr. "There's no bringing him back."
Police say the suspect was riding in an older model Dodge or Chrysler minivan, possibly silver in color.
The suspect is described as a black male, mid-20's to early 30's, 5 feet 7-10 inches, with a medium build. He was seen wearing a light-colored hoodie with an orange wool hat.
"We want to keep his memory alive," said Halbherr. "We want to bring closure to his family, to his friends."
There is a $32,500 reward for the arrest and conviction of the person responsible.
The Philadelphia Parking Authority, where Marshall worked, is posting $10,000.
$2,500 is coming from AFSCME Locals 1637, 696 and 159.
And up to $20,000 is coming from the City of Philadelphia.
To submit an anonymous tip, contact the Citizens Crime Commission at 215-546-TIPS.