JANESVILLE, Wis. -- James Koepp, the man who investigators are calling a suspect in the killing of a family of three near Janesville in January, pleaded guilty on Friday to charges of drunken driving and reckless endangerment.

As part of a plea deal with prosecutors, Koepp entered the guilty pleas in an unscheduled court appearance on Friday morning in Rock County. A charge of fleeing from police and a ticket for being in possession of an open intoxicant in a vehicle were dismissed.

He was immediately sentenced to four years in prison followed by five years of extended supervision.

Koepp, 48, was arrested several days after the bodies of his neighbors, Danyetta Lentz and her two teenage children, were found dead in their home on Jan. 12. He was taken into custody following a high-speed chase in Rock County. While District Attorney David O'Leary said that he planned to charge Koepp with the slayings, no homicide charges have been filed.

Authorities said that Koepp was interviewed about the killings, but then failed to show up for a follow-up interview. A police deputy said that he saw Koepp's car weaving and that Koepp then took police on a 19-minute chase with speeds surpassing 75 mph, WISC-TV reported.

Koepp was accused of fleeing from deputies, and at one point, was driving on the wrong side of the road, causing cars and a tractor-trailer to hit the shoulder to avoid a collision.

Judge Alan Bates said on Friday that he didn't order a pre-sentence investigation because he had already looked through Koepp's entire department of corrections file.

The sentence was a joint recommendation from Koepp's attorneys as well as prosecutors.

After the hearing on Friday, Rock County Deputy District Attorney Perry Folts said that these charges had no bearing on the homicide investigation so his office struck an agreement. He said the investigation into the Lentz family's deaths is continuing.

Earlier this week, Koepp's wife, Nancy Koepp, told The Associated Press on Tuesday that her husband was having an affair with Danyetta Lentz. Nancy Koepp said that she learned of the relationship the night that her husband allegedly fled from deputies.

She said that police have suggested in discussions with her that James Koepp might have killed the family to cover up the affair, but she said that she doubts he had anything to do with the deaths.

Lentz's father, Russ Lucht, said that he spent every weekend with his daughter and that there's no way she was having an affair.

Stay tuned to WISC-TV and Channel 3000 for continuing coverage.