Idaho Murders 911 Call Came from Cell Phone of Surviving Roommate

Turns out the 911 call that reported the slaughter of 4 University of Idaho students came from the cell phone of one of the surviving roommates ... but police aren't saying who called.

The City of Moscow PD clarified its prior statements late Saturday, acknowledging the phone that was used to make the call, but adding, "the identity of the caller has not been released."

It's unclear why cops don't want the ID known, but they have gone back and forth about whether the community is safe, given that the killer/killers are still on the loose.

Police have said they don't believe the surviving roommates were involved in the stabbings. What's puzzling ... authorities believe the murders occurred sometime around 3 AM, but the 911 call wasn't made until noon -- 9 hours later.

Weirdly, the 911 call -- logged at 11:58 AM, November 13 -- requested assistance for an unconscious person ... yet police say it was a bloodbath inside, with blood seeping through the walls onto the exterior of the house.

A big clue seems to be a series of calls made shortly after the victims returned home ... one of them called a guy named Jack a total of 7 times while another tried 3 times, but police offered no further information.

Detectives are on the hunt for surveillance video from 3 AM to 6 AM Sunday, November 13. They're looking at nearby businesses and homes in the area.

It appears some of the victims put up a fight, given they had defensive wounds. Police believe the victims were asleep when the attack began. Police said early on this was a "targeted" attack.

Cops have not found the murder weapon, although they have checked local businesses to see if a Rambo-like knife had been recently sold.