Moscow, May 31 (IANS/RIA Novosti): The father of Ibragim Todashev, the man who was shot dead last week by US authorities while questioning him about the Boston Marathon bombing suspects, said Thursday that his son was killed with a point-blank shot to the head.

The allegation raised even more questions about an already murky case.

"He was questioned for eight hours," Abdulbaki Todashev told reporters in Moscow. "Then they shot him, six times in the body and once in the head."

The May 22 shooting death has been cloaked in mystery, with US media raising questions early on about officials’ use of lethal force - a concern echoed by the dead man’s father.

“They could have wounded him, in the leg or the shoulder. But this is a killing with a ‘control shot’,” Todashev said, using the Russian phrase for a point-blank shot used by hit men to ensure their victim is dead.

He also showed reporters photographs of what looked like his son’s bullet-riddled body, including one of a bullet wound to the head.

“I’ve only seen things like that in movies,” he said in an even, almost detached tone.

The FBI has said it is conducting an investigation into the incident.