An Oklahoma teenager has been accused of stabbing both of his parents and his three siblings to death.

The 18-year-old boy, Robert Bever, was booked by Tulsa police in the suburb of Broken Arrow on five counts of first-degree murder and one count of aggravated assault on Wednesday night, according to The Washington Post.

Another family member was also being held by the police, Bever’s 16-year-old brother. Due to his being a juvenile, his name and the charges against him have not been released, according to Broken Arrow Police Cpl. Leon Calhoun.

Calhoun did confirm that both brothers were cooperating with the investigation of the five bodies that were found stabbed to death across their two-story home.

Even though the two brothers were apprehended and being questioned about the crime, Calhoun says that the police is still trying to find a motive for the crimes. They have begun to search and analyze their social media accounts hoping to find some sort of clues that suggest a motive.

Bever’s Pinterest account showed that he has an interest in Star Wars, the music group Linkin Park as well as sports cars. And his Facebook page only have suggestions of basic information like the High School he attended which was described as a home-schooling curriculum.

Deceased members of Bever’s family include his mother April, 44 and his father David, 53. The Oklahoma State Medical Examiner’s Office also were able to identify the deceased siblings from the stabbings who were Daniel Bever, 12; Christopher Bever, 7 and Victoria Bever, 5.

An unnamed 13-year-old-sister survived the stabbings. The sister found alive and injured, but in stable condition. Also in house was Bever’s 2-year-old sister who was found unharmed and has been placed in state custody.

According to the neighbors in the quiet area, the Bevers kept to themselves and were rarely in sight out and about in the neighborhood. The children were often playing alone in their own backyard or when walking down the street, huddled together. The parents were also noted as not being social.

Father David Bever was described by former co-workers in the IT department at Samson Resources as a very quiet man.

“He was a nice guy, but we weren’t close,” said Lisa Wolfe, Bever’s supervisor at Samson. “I hired him. He worked for us for several years as a contractor. He was a good worker and a nice guy. He didn’t get involved in any office politics, and those are the kind of people I like to work with.

“He liked to do his work and focus on that. He didn’t socialize a lot with the folks he worked with,” Wolfe said.

The crimes were reported from within the home by a 911 caller who were able to tell police that “their brother was attacking their family.”

The 13-year-old sister that was found within the home when officers arrived was bleeding from multiple stab wounds. Police officers were able to communicate with her at that time which is when she told them that “her brothers” were the ones responsible for the attack.

The brothers were found not too far outside the home as footprints in the backyard led to a wooden area where they were immediately found.

At this time police are searching for a motive connected to the brothers, but do not have any leads so far.