TULSA, Okla. – The older of two Oklahoma brothers accused of fatally stabbing their parents and three younger siblings last year was sentenced to life without parole Wednesday after pleading guilty in the killings.

The Tulsa World reports (http://bit.ly/2c5sxA8 ) that 19-year-old Robert Bever was sentenced in Tulsa County District Court after pleading guilty at his scheduled arraignment in the July 2015 killings.

Robert Bever’s brother, 17-year-old Michael Bever, remained silent during his arraignment and a judge entered a not guilty plea on his behalf. Michael Bever’s trial is scheduled to begin next year.

The Bevers were accused of killing their parents, David Bever, 52, and April Bever, 44, and their siblings Daniel, 12; Christopher, 7, and Victoria, 5, in a middle-of-the-night rampage in suburban Tulsa. Two siblings survived.

Robert Bever entered the guilty plea in exchange for an agreement from prosecutors that they wouldn’t seek the death penalty against him.

“While I believe that Robert Bever deserves the death penalty for his savage actions, I feared that a death penalty prosecution would result in his teenage sister being forced to recount and relive the brutal details of the carnage that her brothers wrought again and again,” Tulsa County District Attorney Steve Kunzweiler said in a statement after the sentencing. “The toddler sister, who mercifully was asleep and did not witness the horror, would grow up learning details of the carnage in repeated court hearings that could easily stretch into her teen years or beyond.”

Detectives who testified at a preliminary hearing in February said the brothers detailed to officers a gruesome plot to carry out further mass killings across the country after killing their family.

Detective Eric Bentz of the Broken Arrow Police Department said Robert Bever expressed a desire for notoriety for being a serial killer.

Bentz said at the hearing the teen told of a plan to kill their family, cut up the bodies, and store them in bins in the attic before heading west in the family SUV armed with guns, ammunition and makeshift bombs to randomly attack other locations and kill 10 people at each place.

By many neighbours’ accounts, the Bevers kept to themselves — the siblings played alone in the backyard, walked down neighbourhood streets bunched together and their parents didn’t socialize much. David Bever’s former co-workers at a local IT department described him as a quiet man.