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CHICAGO (CBS) — The family of a local college student killed last year is stepping up their battle to get justice for their son.

The 2 Investigators first reported on the case of Jay Polhill last May, as part of an ongoing investigation into the accuracy of police crime statistics.   

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Now his mother is speaking on television for the first time about the case and a reward the family is offering to anyone who helps catch his killer.

The body of the 20-year-old was found in the Little Calumet River 14 months ago. The Cook County Medical Examiner’s Office ruled his death was caused by “extensive skull fractures” on both sides of his head and a broken neck bone.

But the pathologist said the manner of death was “undetermined.”

Polhill’s family believes that finding stalled the police investigation and was wrong.

“We hired our own pathologist to review Jay’s autopsy and photos,” said Jane Polhill, Jay’s mother. “And that’s their conclusion is that it was a homicide.”

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The Polhills brought those findings to the original pathologist, who later amended her autopsy report. Now the cause of death is “drowning due to multiple injuries due to assault,” a homicide.

“Everything has been a fight. Everything has been a hurdle,” Jane Polhill said.

The Polhills have paid $15,000 to a private investigator to look into the case, and their efforts have prompted the police cold case unit to reinvestigate.   

Now, the parents hope a $10,000 reward the family is offering will move things along.

“I believe that whoever did this to Jay has done this before and will do it again,” the parent said.

Meanwhile, the police officially are still listing Polhill’s case as a “death investigation,” not a murder. So, it is not counted in the city’s 2010 murder statistics.    

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There are several ways to offer information: through a toll-free tip line (866-514-4459); text line (312-985-5642) or by email (centinv@chicagopolice.org).