Bryan Kohberger's DNA was found on a knife sheath at the scene of the Idaho murders ... and authorities made a match by rooting through trash at his family's house and finding his dad's DNA, which had enough of a match to the DNA taken from the sheath for cops to pin the murders on Bryan.

According to the arrest warrant affidavit just released, authorities had Kohberger in their crosshairs less than 2 weeks after the murders. As we reported, cops were on the hunt for a white Hyundai Elantra. On November 13 -- the date of the murders -- there were several videos showing the white Elantra making 3 passes by the murder house before finally stopping at 4:04 AM.

Multiple surveillance videos show the car leaving the area of the murder house at 4:20 AM at a high rate of speed.

Police initiated a video canvas around the murder scene and it appears the car traveled toward Washington State University, which Kohberger attends -- 10 miles from the murder house.

On November 25, cops released info to law enforcement that they were on the lookout for a white Hyundai Elantra. On November 29, a WSU cop pulled up a hit on Kohberger's vehicle and license plate number. Cops went to his apartment in the middle of the night and observed a white Elantra sitting in the driveway.

Now, what we didn't know -- one of the survivors in the murder house says she saw a man 5'10" or taller, not very muscular but athletically built with bushy eyebrows, wearing black clothing with a mask.

Her description is absolutely chilling ... she says the man walked right past her as she stood in a "frozen shock phase," and then he walked past her and left the house.

She had only looked out of her bedroom because she'd heard a female voice, possibly murder victim Kaylee Goncalves, say something like "there's someone here." She also heard a male voice say, "It's ok, I'm going to help you."

Cops got a driver's license picture of Kohberger who had a listed height of 6', 185 lbs and the pic shows he has bushy eyebrows.

Cops say they have WSU cams showing Kohberger's car leaving the campus area at 2:44 AM on Nov. 13. They also have a cell phone number and the records show on the night of the murders, at 2:47 AM the phone left his residence and traveled south through Pullman, Washington. It then stopped reporting, but picked up again at 5:30 AM and showed the phone traveling back to his residence. Cops think he deliberately disabled the phone to conceal his travels.

They also have WSU camera footage of him returning at 5:25 AM.

The cell records also indicate Kohberger returned to the scene of the crime just a few hours later -- between 9:12 AM and 9:21 AM. Worth noting is the fact police were not called to the home until 11:58 AM.

BTW ... the cell phone records also show since June 22, he had been near the murder house at least 12 times prior to the murders, and they were typically in the late evening or early morning hours.

And, there's this ... Kohberger applied for an internship with the Pullman PD in Fall 2022.