A man serving life for killing a child has admitted in court that he strangled his cellmate with a string in the Lino Lakes prison last fall.

Kyle J. Kelbel, 42, pleaded guilty Wednesday in Anoka County District Court to second-degree intentional murder in connection with the October attack on 63-year-old Steven Paul Patchen, who was serving nearly 20 years for criminal sexual conduct.

The plea agreement between the prosecution and the defense calls for Kelbel to be sentenced to a term of 16¼ years, which would run concurrent with his current life term. Sentencing is scheduled for Aug. 12.

Since the killing, Kelbel has been housed in Oak Park Heights prison, the state's highest security facility.

Kelbel is serving a life sentence for first-degree murder out of Ramsey County stemming from the December 2000 killing of his girlfriend's 2½-year-old daughter, Kailyn Montgomery, in Maplewood.

According to prosecutors in the strangulation case:

Kelbel told a corrections officer on Oct. 5 that Patchen was dead and that he killed him. Patchen was declared dead in his cell less than 20 minutes later.

Kelbel told state Bureau of Criminal Apprehension (BCA) agents that he "just snapped" and beat Patchen, the complaint read.

The night before, Kelbel continued, he and Patchen argued. Also, Kelbel added, Patchen said something about a young female relative of Kelbel's.

Kelbel said he grabbed Patchen from his lower bunk, slammed him to the floor, and punched and kicked him. He said he took a string used to hold the cell door open and strangled him with it.

After Patchen died, Kelbel continued, he put his cellmate in clean clothes, placed him in the bunk, covered him up and positioned him on his side to make him appear to be sleeping. Kelbel then went to sleep.

Kelbel said he awoke the next morning, went to a prison common area and told someone during a phone call that he killed Patchen.

"Concerned that guards had not discovered that [Patchen] was dead, [Kelbel] alerted a guard at 11:10 a.m.," the charging document read.