The father of a Chechen immigrant killed while being interrogated by the FBI about his ties to a Boston Marathon bombings suspect says agents killed his son "execution style."

At a press conference Thursday in Moscow, Abdul-Baki Todashev showed journalists 16 photographs he said were of his son, Ibragim, in a Florida morgue. He said his son had six gunshot wounds to his torso and one to the back of his head and the pictures were taken by his son's friend, Khusen Taramov.

It was not immediately possible to authenticate the photographs.

The FBI says 27-year-old Ibragim Todashev was killed during a violent confrontation last week while being questioned about his ties to slain Boston Marathon bombing suspect Tamerlan Tsarnaev, as well as about a 2011 triple slaying in Massachusetts.