CHICAGO -- A DeKalb, Ill., man was sentenced Wednesday to 37 years in prison for murdering a college freshman in a plea deal that was criticized by the victim's family and a former prosecutor, but defended by the state's attorney as the right decision to protect the public.

William P. Curl, 36, agreed to plead guilty to the first-degree murder of Antinette "Toni" Keller, 18, a Northern Illinois University student from Plainfield whose burned remains were found in a DeKalb park in October 2010, after the art student told friends she was going there to do some sketching.

Although he pleaded guilty, Curl still maintains that he did not kill Keller, said his attorney, DeKalb County Public Defender Tom McCulloch. The hearing before Judge Robbin Stuckert in Sycamore was interrupted almost immediately when a woman identified as a relative of Curl's shouted out from the audience that Curl should not accept the plea deal.

"Billy, don't take it. They are railroading you," the woman blurted out. She continued to speak up loudly as security officers removed her from the courtroom. Even after her removal, she could be heard saying "He didn't do it," in a loud voice from the hall.

She was not the only critic of the outcome.

Toni's parents, Diane and Roger Keller, thought the sentence was too lenient, according to a family spokeswoman. They were not in court Wednesday.

"To be there would almost be a display of support (of the deal) in some respect," Toni Keller's cousin Mary Tarling said. "And Roger and Diane do not feel like they want to support the outcome of this.

"They're just very concerned that there's this release date" from prison for Curl, Tarling said, "that there's this window of light and hope" for him.

Curl must serve 100 percent of the sentence, minus credit for about 21/2 years spent in jail awaiting trial.

Had Curl been convicted on all counts, he faced a maximum sentence of 75 years in prison, according to prosecutors, who dropped charges of sexual assault and arson as part of the negotiated plea.

On a Facebook page dedicated to Toni, a message was posted in which Diane Keller says she felt let down by the terms of the plea deal.

"My family is so tired of suffering. My baby girl is gone," the message read.

Although no family members attended the hearing, former State's Attorney Clay Campbell was in the audience. Afterward, he said the 37-year prison term was "outrageous" for someone who "raped, murdered and incinerated" Keller. Equally outrageous, Campbell said, was Curl maintaining his innocence.

"At a minimum, he should have been required to stand before the court and admit his guilt to this horrible crime," said Campbell, who said he met with Keller's parent many times during his two years as state's attorney.

McCulloch said Curl is legally allowed to agree to a plea deal and deny responsibility for the crime.

State's Attorney Richard Schmack, who defeated Campbell in last November's election, said there would have been challenges to a trial, which was scheduled for this month, including the possibility that a jury could acquit Curl.

"We think it's a just result," Schmack said at a news conference following the hearing. "We have served the public and served Toni by bringing her murderer to justice."

He did acknowledge, though, that there had been some gaps in communication in recent days with the Keller family caused by the holiday weekend and the fast-developing nature of the plea negotiations.

Schmack laid out some possible prosecution pitfalls, including the lack of an eyewitness, murder weapon, a time or cause of death, or a confession. In addition, Keller's body was so badly burned that authorities had limited forensic evidence, he said.

Keller left her dormitory on Oct. 14, 2010, telling friends she planned to do some sketching in DeKalb's Prairie Park. Her charred remains were found days later, along with some of her possessions. Witnesses placed Curl at the park that day, and friends later told authorities that they had seen deep scratches on Curl's chest. He reported getting them during a sexual encounter with a woman he met at the park.

Curl was interviewed by police in the days after the crime, but failed to appear for a second interview. He was traced to Louisiana, where he was arrested. Curl initially told police that he had never met Keller, and then changed his story, saying he found her dead body in the park and burned it, Assistant State's Attorney Stephanie Klein said. He then told police that he and Keller were having sex in the park when she suffered a seizure, hit her head on a rock and died, Klein said.

(Ward is a freelance reporter. Manchir is a Chicago Tribune staff reporter.)

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