William Curl (DeKalb Co. Booking Photo), Antinette Keller (Personal Photo)

William Curl (DeKalb Co. Booking Photo), Antinette Keller (Personal Photo)

UPDATED: 4/2/2013 – 5:22 p.m.

DEKALB, Ill. (CBS) — The family of a Northern Illinois University freshman who was slain three years ago were pleading with prosecutors on Tuesday not to let the girl’s accused killer cut a plea deal.

CBS 2’s Mike Puccinelli reports Antinette “Toni” Keller’s parents want 36-year-old William “Billy” Curl to stand trial, rather than be allowed to avoid a possible life sentence by working out a plea agreement.

Curl is accused of killing Keller and leaving her burned remains in a local park in October 2010.

DeKalb County prosecutors announced a tentative plea deal with Curl on Tuesday. Curl was set to stand trial in the case next week.

After a hearing in the case on Tuesday, Keller’s parents left the DeKalb County Courthouse without commenting on camera, letting a letter they posted on Facebook speak for them.

In it, Diane Keller railed against a possible deal that would send Curl to prison for 37 years in exchange for his guilty plea.

She wrote that the Keller family wants prosecutors to take Curl to trial “to prosecute a murderer who threw my baby in a firepit and burned every freckle on her face, every beautiful piece of her.”

Curl is accused of attacking Keller as she walked Oct. 14, 2010, in Prairie Park, near the NIU campus, and burning her remains. Search teams found the remains two days later; she was identified through a DNA match.

Curl became the focus of the case when he failed to appear for a second interview with investigators. Police allege that he hid briefly in Mexico before returning to the U.S.

Federal marshals arrested him in Louisiana, and he was extradited for trial.

He was indicted in January 2011 on charges of murder, arson, criminal sexual assault and concealing a homicidal death.

Curl’s public defender, Tom McCulloch, said the Keller family’s anger isn’t surprising.

“It would be an exception when a victim comes in and says, ‘treat the defendant kindly,’ or anything different,” he said.

Laura Devine was a fellow art student at NIU in October 2010, when Keller was killed, so she felt compelled to be there Tuesday when Curl was lead into court in chains.

“I just can’t believe he’s a person, that he’s real, that he did that,” she said.

Under terms of the deal – which could be finalized in court on Wednesday – Curl would spend the next 37 years behind bars, with no time off for good behavior.

But to the Keller family and their loved ones, that’s not enough.

Family friend Thelma Holdeniss said, “Toni’s never coming back. She’s never coming back, and for people who live here, this has forever changed us and our town.”

Diane Keller said living without her daughter amounts to a life sentence; a sentence she believes Curl will escape with the plea deal. He would have faced up to 60 years in prison if convicted at trial.