Idaho prosecutor Bill Thompson said investigators can’t rule out the possibility that Bryan Kohberger used a second weapon during the murders of four University of Idaho students and believes the killer spared surviving roommate Dylan Mortensen because he panicked and fled, according to an interview with the Idaho Statesman.

Thompson explained that some injuries observed on victim Kaylee Goncalves, 21, appeared to have been caused by something other than the knife used in the attack, though he stopped short of confirming a second weapon. 

“There were injuries that appeared to have been caused by something other than the knife, although it could have been the knife,” Thompson told the Statesman. “I don’t think we can exclude the possibility that there was an additional weapon involved.”

Court documents revealed the extent of the November 2022 attack on Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin. Goncalves, authorities revealed in recently released Moscow Police Department documents, endured “more than 20 stab wounds,” alongside blunt-force trauma.

Mortensen shared with authorities that she had noticed an intruder with “bushy eyebrows” on the night of the attack on 1122 King Road in Moscow, who had told her that he was “here to help.”

James Fry, who was chief of the Moscow Police Department at the time, told ABC News that there are many theories as to why Mortensen survived, including that Kohberger may have been exhausted from the quadruple murders.

“I don’t know, only he has that answer,” Fry told the outlet.

Thompson also emphasized the critical role DNA evidence played in solving the case. 

“From our perspective as prosecutors, the DNA was critical to the strength of the case for trial purposes,” he said. 

Without the DNA linking Kohberger to the knife sheath, securing a conviction might have been “insurmountable,” Thompson told the Statesman.

Fox News Digital has reached out to the Latah County Prosecutor’s Office for comment.