Updated 06/17/12 – 4:23 p.m.

CHICAGO (CBS) — Police were offering a reward for information leading to the arrest of whoever sprayed graffiti on the Gold Star Families Memorial to fallen police officers near Soldier Field.

The fountains at the South Loop park dedicated to fallen officers offered a peaceful backdrop Sunday morning for a Father’s Day service, but it was hard for police officers and their family members to ignore the graffiti that had been sprayed on the memorial wall on Thursday.

“I feel for the families here, because they’re coming down here to pay respect to their loved one, and then they have to see something that’s just been spoiled like this,” Chicago Police Memorial Foundation executive director Phil Cline said. “It’s a despicable act. It’s disrespectful to the families whose fathers are named on that wall.”

City workers removed the red spray paint from the north end of the memorial, located near 18th Street and McFetridge Drive, before Sunday’s memorial mass at the park.

LISTEN: WBBM Newsradio’s John Waelti reports

Police said someone sprayed the graffiti on the wall sometime before 6 p.m. on Thursday, when the vandalism was discovered.

Cline said it appeared to be a simple act of tagging.

“The taggers have signatures, so we’re hoping somebody can look at that and say he recognizes the signature on it,” Cline said.

The Chicago Police Chaplain’s Ministry and the Chicago Police Memorial Foundation are offering a $3,000 reward for information leading to the arrest and conviction of those responsible.

Chicago Police Chaplain Dan Brandt said he has faith his fellow officers will catch the vandals.

“I think our fine Police Department will track down the bad guys, and they’re going to tag the wrong place at the wrong time, and they’ll get caught,” he said.

Cline said he’s optimistic the reward will be effective in convincing someone who knows something to come forward. Anyone with information should call Area Central Detectives at 312-747-8382.

Police are now considering putting cameras throughout the park.

Watch & Listen LIVE