Michael Bever was slated for a status conference hearing Monday in the deaths of five family members. It was originally the day his jury trial was to begin.
The trial was again delayed, this time until next April. Bever is charged with five counts of first-degree murder and one count of assault and battery.
He's accused of stabbing his parents and three siblings to death in their home in Broken Arrow.
Attorneys asked for and received delays in the murder trial in May 2017. That's when the defense produced a report saying Bever was so under the influence of his older brother Robert that he wasn't able to form "intent" to commit the crimes.
At that time, the district attorney told the judge it needs to have its own expert evaluate Bever and wasn't sure that could be done by the June 5th trial date. The judge agreed and set the trial for August 28, 2017.
Police say the Bever brothers planned out the murders, even ordered ballistic clothing, guns and knives in hopes they might become more famous than other mass killers.
Police say the brothers planned to chop up their family's bodies and put them in plastic tubs before the brothers drove across the nation, killing random people.
Authorities also say Michael, who was 16 at the time, even banged on the office and bathroom door, where younger siblings were hiding, and begged to be let in, because he feared he would be killed. Police say when the children opened the doors, they were murdered.
A 2-year-old sister wasn't harmed and a 13-year-old sister survived her stab wounds. The 13-year-old is set to testify against her brother in trial.
The older brother, Robert, pleaded guilty to the crimes and is serving five sentences of life without parole.