PHILADELPHIA (WPVI) -- The reward to catch the vandal who defaced the mural in memory of slain Philadelphia Police Sergeant Robert Wilson, III has grown.After a $10,000 promise from the Sheetmetal Union Local 19 Friday night, the reward now stands at $32,500. Sergeant Robert Wilson III was gunned down four years ago inside a GameStop on March 5, 2015.A mural that was created in his honor was vandalized sometime Thursday morning on the 2900 block of Ridge Avenue.The Philadelphia FOP Lodge #5 originally offered a reward of $10,000. Numerous residents and organizations then contributed to the reward including $5,000 from IBEW Local #98 and $2,500 each from the Steamfitters Local #420 and Brian McMonagle & Fortunato Perri Attorneys."It's sickening and disgusting that some low-life would deface the mural of hero and fallen-officer, Robert Wilson III," said FOP Lodge #5 President John McNesby. "We will never forget Rob's bravery, courage and valor when he saved lives inside that GameStop store."Anyone with any information is asked to call police at 215-686-TIPS.