New details revealed of surviving roommate's interview with police after Idaho college murders

BOISE, Idaho -- Bryan Kohberger, the man accused in the Idaho college murders, is back in an Idaho courtroom this week as his defense team fights to throw out DNA evidence in the case.

There were stunning revelations in a Boise courtroom as Kohberger's defense team tried to paint the investigation as flawed and shrouded in secrecy in an effort to get key evidence thrown out.

"This is a situation where this identification was done in complete secret behind closed doors," said Kohberger's lead defense attorney, Anne Taylor.

The former PhD student is accused of stabbing four University of Idaho students to death in their off campus apartment.

Taylor revealed details of a surviving roommate's interview with authorities in the aftermath of the gruesome quadruple homicide.

"There are two references to not remembering. And a couple of days later in the third interview, there are references to not remembering, being drunk," she said. "A statement, 'I don't know any of it, like half this stuff I don't know if it was a dream or if it's real.' And credibility is really, really important when this person was relied on in the investigation."

RELATED: Idaho college killings: Prosecutors push back against Kohberger requests to exclude key evidence

Taylor added the roommate told police she had been drinking and that she also heard one of the victims come up and down the stairs during the time of the attack.

"They know that fact is wrong," Taylor added.

Taylor said that information was never provided to the judge at the time, laying the groundwork for her to question the beginning of the investigation and collection of evidence, including DNA that authorities say was found on the button snap of a knife sheath at the crime scene.

Investigators also used investigative genetic genealogy to link Kohberger to the crime, which is a tactic Taylor has long argued is flawed.

"Investigative genetic genealogy, or IGG, is the process by which law enforcement will take a sample of DNA and initially probably run it through what's called CODIS, a federal criminal database. But if there's no hit there, then law enforcement can take that DNA to a genetic genealogy database and see if they can take information from that database to see if that sample is related to someone," explained ABC News legal contributor Brian Buckmire.

Kohberger's DNA was later matched to trash pulled from the Pennsylvania Poconos neighborhood where he was with his parents when arrested.

RELATED: Bryan Kohberger's defense reveals alleged details from night of arrest at parent's Pennsylvania home

Kohberger's lawyers are accusing the FBI of not having a warrant to work with the trash collection company.

"I think it's interesting when you have the FBI telling the trash man what to do," Taylor said in court.

"An individual has no expectation of privacy as to what they throw into the trash, and so law enforcement wouldn't need to get a warrant to check what they call as an abandonment sample," Buckmire explained.

The prosecution countered Taylor's argument by saying no rights were violated and that they relayed the evidence based on what they knew at the time.

"There was nothing obtained that violated the defendant's constitutional rights," said Deputy Prosecuting Attorney Ashley Jennings. "The defendant has failed to submit any false statement or admission, without which the magistrate would not have found probable cause."

The proceedings were private for most of the first day until cameras were turned back on briefly. The family of victim Kaylee Goncalves was then able to watch the stream in the courthouse.

The hearing will continue Friday, where the Goncalves family is hoping they will be allowed into the courtroom.

Kohberger's trial is still slated to start in August, where he faces the death penalty.