CHICAGO (CBS) — PETA is joining the effort to find who was responsible for leaving a pit bull puppy left to die in garbage bags in Willow Springs last week.

The animal advocacy organization is offering $5,000 for “information leading to the arrest and conviction on cruelty-to-animal charges,” PETA said in a news release.  It’s also providing free posters to download (available here) for anyone who wants to help.

His rescuers named him Vinny. The dog was found near Forest Avenue, north of West 87th Street. The three-year-old was taken to the South Suburban Humane Society where workers discovered he was suffering from dehydration and has kidney issues.

“Someone bagged up this dog and threw him out on the side of the road like a piece of trash,” says PETA Vice President Colleen O’Brien. “PETA urges anyone who recognizes him to come forward immediately so that whoever left him to die alone in the cold can be held accountable.”

The dog found days ago in double bagged trash bags. Tied at the top. Vinny was alive, but Cook County Animal and Rabies Control warden John Haralamos knew it was no accident.

“I was the one who got the call (of a) dog dumped on the side of the road,” said John Haralamos. “They knew that dog was alive when they put Vinny in the garbage bag.”

But who did it still a mystery. Officers found the pit bull in Willow Springs on Forest Avenue. It’s a wooded area and no apparent owner in sight.

Vinny now has to gain weight. He also has kidney issues. The team at South Suburban Humane Society now has the task of getting him to trust the ones who care for him.

“If he had been there very much longer, he would be dead. Of course, we don’t know what really happened before he was found on Monday, but it can’t have been good,” said Emily Klehm, CEO of the South Suburban Humane Society. “And so he’s afraid of humans.”

But with no apparent leads in the investigation, officials are desperate.

Anyone with information is asked to contact the Cook County Sheriff’s Office at 847-635-1188.