Lawyers for convicted Boston bomber Dzhokhar Tsarnaev called a psychiatrist to the stand on Tuesday to help support claims of dysfunction in their client’s family.

The Associated Press noted that Dr. Alexander Niss, a psychiatrist who treated Tsarnaev’s father between 2003 and 2005, said that he showed signs of post-traumatic stress disorder.

The doctor told the court that Anzor Tsarnaev exhibited the most common signs related to the disease including anxiety, panic attacks, flashbacks and paranoia. He testified that his former patient began suffering from the symptoms after he said he was tortured in a Russian camp during the Russian-Chechen war in the 1990s.

The convicted bomber’s attorneys have claimed that both of his parents suffered from mental illnesses and Niss’ testimony seemed to lay the groundwork for that theory.

As previously reported, a day earlier some of Tsarnaev’s family members took the stand and pleaded for the 21-year-old’s life.

Tsarnaev was found guilty last month on 30 counts for the 2013 Boston Marathon bombing. Now, in the trial's death penalty phase the jurors must decide whether he should be executed or spend the rest of his natural life behind bars.

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