the gunman's father, met with reporters outside his Port St. Lucie, Fla., home where he offered both an apology for his son's actions and a belief that the radical influences of the Islamic State, also known as ISIS or ISIL, had apparently overtaken his son without his knowledge.

"ISIS is the most dangerous group on the face of the earth,'' he said. In addition to the Islamic State, the gunman also pledged his solidarity with the Boston Marathon bombers and an American-born suicide bomber who died in a 2014 attack in Syria.

As recently as Monday, FBI Director James Comey said it was "not entirely clear'' what terror interest the gunman sought to support.

The father, in an often-rambling appearance, also suggested that the club's security system was inadequate, once referringto it as "sloppy.''

Though he pledged to cooperate with investigators, he said no other members of his family are "involved in this.''

He did not answer specific questions about his daughter-in-law's possible knowledge of the plot, except to describe her as the "most sincere, most wonderful lady that I have known.''