Tamerlan Tsarnaev, the 26-year-old suspected Boston Marathon bomber, was haunted by voices and feared that someone was gaining control over his mind prior to the devastating attack, according to a new report by The Boston Globe.

Tamerlan’s younger brother, Dzhokhar, 20, is also accused of carrying out the April 15 bombing, which killed three and injured more than 260. Though Tamerlan died during a shootout with police days after the incident, Dzhokhar was apprehended and faces the death penalty if convicted.

After a five-month investigation into the suspected bombers' backgrounds, the Globe has published a lengthy piece that paints a startling portrait of the dysfunctional Tsarnaev family. Drawing from reporting in the U.S., Kyrgyzstan, Russia and Canada, the Globe claims that the motivation behind the bombing was “more likely rooted in the turbulent collapse of their family and their escalating personal and collective failures" than in what federal investigators suspect to be a jihadist agenda.

The report points to warning signs that Tamerlan was suffering from mental illness and “had some form of schizophrenia,” a family friend told the newspaper.

“He [Tamerlan] had told his mother that he felt there were two people living inside of him,” Anna Nikaeva, another family friend, told the Globe. “I told her, ‘You should get that checked out.’ But she just said, ‘No, he’s fine.’"

According to an interview with Tamerlan’s close friend, Don Larking, whom he met at his local mosque, Tamerlan was worried that uncontrollable voices in his head were directing him to do something he didn’t want to do.

“He believed in majestic mind control, which is a way of breaking down a person and creating an alternative personality with which they must coexist,” Larking told the Globe. “You can give a signal, a phrase or a gesture, and bring out the alternate personality and make them do things. Tamerlan thought someone might have done that to him.”

Mental illness has been linked to several recent mass murders.

In September, U.S. law enforcement officials told The Associated Press that Aaron Alexis, identified as the man who killed 12 and died during a shooting rampage in a D.C. Navy Yard, had been hearing voices but had not been deemed mentally unfit for his security clearance.

James Holmes, who is accused of opening fire and killing 12 in a sold-out Colorado movie theatre last year, entered a plea of not guilty by reason of insanity earlier this year.

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  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev practices boxing at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts. These images show what is believed to be Boston bomber Tamerlan Tsarnaev boxing at the Wai Kru Mixed Martial Arts center in Boston, MA. The native Chechnya, dubbed Suspect 1 by the FBI, and has been reported as dead. He was described as a heavyweight fighter at the gym, and allegedly hoped to fight for the US, because his home nation was not recognised in the sporting world.

  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev practices boxing at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts.

  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev practices boxing at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts.

  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev arrives at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts.

  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev practices boxing at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts.

  • BOSTON, MA - APRIL 2009: Tamerlan Tsarnaev practices boxing at the Wai Kru Mixed Martial Arts center in April 2009 in Boston, Massachusetts.