PITTSBURGH (AP) — Lawyers for the gunman who killed 11 people at a Pittsburgh synagogue requested a court order Tuesday to exhume the body of his long-dead father.

Robert Bowers’ lawyers want the body exhumed for a DNA test after federal prosecutors raised questions about paternity during the penalty phase of Bowers’ trial for the 2018 massacre at the Tree of Life synagogue.

Bowers, a 50-year-old truck driver from suburban Baldwin, was convicted in June on 63 criminal counts in the nation’s deadliest antisemitic attack. A federal jury has to decide whether to sentence him to death or life in prison without parole.

Other news Synagogue gunman had traumatic childhood and couldn’t function as an adult, defense expert testifies The perpetrator of the 2018 Pittsburgh synagogue massacre had a deeply unstable life from childhood through his adult years. How the death penalty phase of the Pittsburgh synagogue gunman’s trial might play out The federal trial of a 50-year-old truck driver convicted of killing 11 people at a Pittsburgh synagogue in the deadliest antisemitic attack in U.S. history is in its third and final phase. Pittsburgh synagogue attack survivors testify about overcoming physical and emotional wounds Survivors of the 2018 Pittsburgh synagogue attack have testified to the severe physical and emotional injuries they suffered during the deadliest antisemitic massacre in U.S. history. Jurors weighing fate of Pittsburgh synagogue killer hear of the devastation he left behind A prosecutor is asking jurors to impose a death sentence on the gunman who killed 11 worshippers at a Pittsburgh synagogue, saying Robert Bowers targeted them because of their faith and has never once expressed remorse.

The defense, trying to show that Bowers has a family history of mental illness, has introduced evidence that his father, Randall Bowers, was diagnosed with schizophrenia. The defense asserts Robert Bowers also has schizophrenia and opened fire at the synagogue out of a delusional belief that Jews were helping to commit a genocide against white people.

Randall Bowers died by suicide in 1979 on the eve of his own rape trial. At trial last week, prosecutors sought to cast doubt on whether he was Robert Bowers’ biological father. The defense asked a judge on Tuesday to clear up the matter by ordering the exhumation of Randall Bowers’ body.

“The Department of Justice presumably shares the defense’s concern with seeking the execution of a seriously mentally ill person. That the government is vigorously contesting, albeit on flimsy evidence, that Randall Bowers is the biological father of Robert Bowers indicates that it too believes that paternity matters and is significant,” defense lawyers wrote.

The government was expected to contest the defense motion.

The defense, seeking to persuade the federal jury to spare Bowers’ life, has been trying to show that Bowers had a deeply traumatic childhood marked by abuse and neglect, and that he threatened or attempted suicide multiple times in his teens, including by setting himself on fire. Prosecutors say Bowers was motivated by his hatred of Jewish people and spent six months planning the synagogue attack.