The friends of Chattanooga shooter Mohammod Youssef Abdulazeez fired off alarmed texts to each other in the hours following the killings.
"It can't be our abdulaziz [sic] .." wrote James Petty, a close friend of Abdulazeez, who gave the texts to CNN on condition none of the other people in the conversation be named.
Abdulazeez opened fire at two military sites in Chattanooga last week, killing four Marines and one Navy sailor.
Toward the end of the conversation, one friend texted, "This was his choice. May Allah forgive him and us all. Ameen," to which someone said, "bro there is no foigivrness [sic] for taking innocent lives."
Petty also told CNN that Abdulazeez was not inspired by ISIS and thought the group was against Islam.
At a press conference on Wednesday, Ed Reinhold, the FBI's special agent in charge in Knoxville, told reporters it was too early to know if Abdulazeez was "radicalized."
He said authorities are treating him as a "homegrown violent extremist" who apparently acted alone.
Reinhold also provided details on what exactly happened at both facilities last Thursday.
He said Abdulazeez first drove to a recruiting office and opened fire without getting out of his car. He then drove seven miles away to a joint Marine-Navy facility, where he crashed through the gates.
The gunman then went inside the facility, shooting and killing one service member, Reinhold said. He then went back outside to the motor pool area, where he shot and killed four more troops.
Abdulazeez was eventually "engaged" by Chattanooga police officers, who returned fire and killed him, Reinhold said.