A man who killed four people in a 1999 drunken driving crash pleaded guilty Monday to driving under the influence again, on the same road, in February 2013 in McHenry County.
Walter J. Depner, 62, of Mount Prospect, faces up to 10 years in prison for aggravated DUI.
Because of Depner's past, he is eligible for an extended term and probation is not an option.
McHenry County Assistant State's Attorney David Metnick said prosecutors will argue for the top sentence from McHenry County Judge Gordon Graham Aug. 29.
"The (state's) offer from Day 1 was no less than the maximum of 10 years," Metnick said. "That's still our position. We still feel that's what he deserves."
In August 1999, Depner killed four members of a Crystal Lake family -- Eva Burleson, 34, and her children, Daniel, 14, Tiffany, 11, and Dallas, 7 -- who were returning from Great America.
Her husband, Thomas Burleson, was driving and was seriously injured but survived the crash in which Depner's minivan crossed the centerline on Route 120 near Lakemoor and collided head-on with the Burlesons' Volkswagen Microbus.
No one was injured the night of Feb. 24, 2013, when Depner was spotted driving erratically in a pickup truck east again on Route 120 in McHenry, Metnick said.
Depner's pickup truck plowed through a snowbank, and authorities were called to a home where Depner was found lethargic and under the influence of alcohol.
He later told people in the house he took 30 to 40 anti-anxiety prescription pills that Depner admitted to authorities belonged to his girlfriend, Metnick said.
Depner also had problems standing up and was mumbling about an accident that occurred more than 10 years ago.
"He said, 'I took a bottle of klonopin, I hope it's enough,' " Metnick said of Depner.
Metnick also said Depner admitted to drinking; a blood test later showed his blood alcohol concentration was .03.
While that concentration is below the legal threshold, Metnick said test results also showed benzodiazepines in Depner's bloodstream and the experts were prepared to testify if the case went to trial that Depner was impaired because of the alcohol and drug combination.
Metnick said Depner's bond was revoked after he pleaded guilty and he was taken to the McHenry County jail.
A message left at Donahue and Walsh, the law firm representing Depner in this case, was not immediately returned Monday.
Under state law, Depner can have his prison sentence cut in half for good behavior behind bars.