By CBS3 Staff

PHILADELPHIA (CBS) – A mural honoring the service and sacrifice of a Philadelphia police officer killed five years ago while trying to stop a robbery has been defaced. Graffiti was found on the mural of  Sgt. Robert Wilson III at 60th Street and Baltimore Avenue.

Spray-painted on the mural were the acronyms “ACAB” and “FTP” which are two anti-police slogans, as well as a symbol used by anarchists. Late Sunday, the artist responsible for the mural removed the graffiti.

FOP President John McNesby tweeted Sunday morning saying they were aware of the issue and are working to get it fixed.

“I’m saddened and angered that vandals would deface the mural of one of our beloved heroes,  Sgt. Robert Wilson III,” McNesby said in a statement. “Our thoughts and prayers are with the Wilson family on this sad day. Wilson served our great city with passion and compassion and is sorely missed by his friends and colleagues in the Philadelphia police department.  Rest easy, Robb.”

Wilson was shot and killed in 2015 while trying to stop a robbery inside of a GameStop at 21st Street and Lehigh Avenue. Police say he was there to buy his young son a gift.

Philadelphia Police Sgt. Robert Wilson

Credit: CBS3

Police say Wilson’s bravery saved the lives of others inside the store.

Authorities arrested Ramone Williams and Carlton Hipps and charged them with murder. They say both men are seen on surveillance video shooting Wilson inside the store. They were sentenced to life in prison with no parole plus 50 to 100 years in 2018 in a plea deal that spared them the death penalty, angering the police union and some of the victim’s family members.

The police union is offering a $10,000 reward for information leading an arrest in the incident.

Another mural honoring Wilson in the city’s Strawberry Mansion section was defaced last year.