DAYTON — Cody Henderson, accused of killing his stepfather, pleaded guilty to all indicted charges Friday, sparing himself the death penalty.

Under the plea agreement reached with the Montgomery County Prosecutor’s Office, Henderson, 21, will spend the rest of his life in prison. Henderson, of Madison Twp. in Butler County, also forfeited his right to appeal on most issues.

Henderson pleaded before a three-judge panel of Mary Wiseman, Dennis J. Langer and Frances E. McGee to aggravated murder, aggravated robbery, felonious assault and tampering with evidence. He also pleaded guilty to the death penalty specifications: that he committed the murder for hire, and that he committed the murder while committing, attempting to commit or fleeing after committing aggravated robbery.

Henderson was to go on trial June 20. After he signed the plea forms, prosecutors called a forensic pathologist to testify for the judges about the wounds of Charles Zan, then a Miamisburg detective. The testimony was necessary as Henderson pleaded to the death specifications, even though he will not be executed.

The judges deliberated for about 20 minutes in chambers before deciding unanimously that the prosecutors proved the charges and specifications beyond a reasonable doubt, accepting his plea.

Addressing the judges, Henderson offered “my sincerest apologies” to Zan’s family, adding “I do feel guilty and I am sorry for what I have done.”

The panel then unanimously sentenced Henderson to life in prison without the possibility of parole for the aggravated murder conviction plus 15 years for the other charges, to be served consecutive to the life sentence.

Charles Zan’s family members declined to make a victim impact statement or to comment after the daylong hearing.

All counts concern the Oct. 17, 2009, slaying of Zan, 45, who died from 48 stab wounds during an early morning attack at the Zans’ Miamisburg apartment. Prosecutors said Henderson plotted the attack with his mother, Pandora Zan, and Henderson committed the stabbings while his mother waited outside.

Pandora Zan, 46, was convicted March 25, after a two-week trial, of complicity to commit murder, complicity to commit aggravated robbery, two counts of tampering with evidence and one count of obstruction of justice. Wiseman sentenced Zan on April 21 to life without the possibility of parole plus 25 years.

“We think that justice was served today,” said assistant county prosecutor Dan Brandt, who prosecuted the case with assistant county prosecutor Erin Claypoole. “He will never see the light of day and he will die in a prison cell.”