A truck driver suspected of the Pittsburgh Synagogue massacre during Shabbat services last October pleaded not guilty to over 60 charges connected to atrocity at a federal court on Monday.
Prosecuters allege Robert Bowers, who was shackled when he appeared in court, of murdering 11 people at the Tree of Life Synagogue among other charges.
Seven people were also wounded, including five police officers.
Pittsburgh prosecutors intend to seek the death penalty against Bowers though the US Attorney General will make a ruling.
His new lawyer, Judy Clarke, has indicated he may consider a plea bargain.
Clarke is renowned for negotiating deals for notorious killers to avoid the death sentence.
Deals were struck for Atlanta Olympics bomber Eric Rudolph, Unabomber Ted Kaczynski and Arizona killer Jared Lee Loughner.
Boston Marathon bomber Dzhokhar Tsarnaev though was sentenced to death.
Bowers, 46, of Baldwin, Pennsylvania, initially faced 44 charges before a grand July added a further 29 last month.
Additional charges include hate crimes, obstruction of religious belief and use of a firearm during crimes of violence.
He is being held in Butler County Prison, around 35 miles north of the Synagogue.
By Howard Lawrence