Bryan Kohberger’s sister searched his car for evidence before police swooped in

Sources told NBC’s Dateline that the accused killer’s family searched his white Hyundai Elantra for possible evidence of the Idaho college murders

Bryan Kohberger’s sister feared that her brother was involved in the stabbings of four University of Idaho students before police swooped on their parents’ home and arrested him for murder, according to a bombshell report.

Sources told NBC’s Dateline that one of the accused killer’s older siblings grew increasingly suspicious of her brother and his behaviour when the family gathered to spend the holidays together.

Her suspicions were so great that – at one point – several family members searched Mr Kohberger’s white Hyundai Elantra for possible evidence of the crime, they said.

Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin were found brutally stabbed to death in the off-campus home in Moscow, Idaho, that the three women shared with two other roommates on 13 November.

For more than six weeks, no suspects were publicly identified and leads appeared to have gone cold.

In mid-December, Mr Kohberger – a 28-year-old criminology PhD student at Washington State University (WSU) – embarked on a cross-country trip with his father from his student rental home in Pullman, Washington, back to the family home in Albrightsville, Pennsylvania, to spend the holidays together.

But, during his time at home, his family members noticed that he was behaving somewhat bizarrely.

The source said that Mr Kohberger was constantly wearing latex gloves, including inside their own home.

One of his two older sisters began to wonder if he could have played a part in the murders – and, at one point, she raised her concerns with her other family members.

She “loudly pointed out” that, at the time of the murders, her brother was living just a few miles from the crime scene and that he drove a white Hyundai Elantra – the make and colour of vehicle at the centre of the investigation.

Along with his bizarre tendency to wear latex gloves at all time, she believed that the family should consider that Mr Kohberger might have killed the four victims, the source said.

Mr Kohberger’s father allegedly defended his son and insisted he could not have been involved.

But the concerns were clearly big enough for several of the family members to reportedly decide to search the 28-year-old’s vehicle to look for possible evidence.

Bryan Kohberger is accused of killing Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin (PA police)

By that point, police said Mr Kohberger had already been spotted cleaning his car out with bleach and so the family members didn’t find anything of note, the source said.

It is not clear if Mr Kohberger was aware of his family members’ suspicions that he could have been behind the murders – or what prior behaviour may have led his own sister to suspect him capable of carrying out such a brutal crime.

Soon after, in the early hours of 30 December, law enforcement descended on the family home and arrested him for the murders.

At the time of his arrest, the source said Mr Kohberger was wide awake standing in the kitchen wearing latex gloves and putting his personal trash in plastic bags to take it out to a neighbour’s trash can.

An attorney close to Mr Kohberger’s family declined to comment on the revelations outlined in Dateline’s “The Killings on King Road”.

On Monday (22 May), he will appear in court for his arraignment on four counts of first-degree murder and burglary.

The 28-year-old is scheduled to be arraigned in Latah County Court in Moscow, Idaho, where he is expected to enter a plea on the charges.

Mr Kohberger had been due to appear in court for a week-long preliminary hearing on 26 June, where the prosecution would lay out the case and evidence against the suspect.

However, on 16 May, a grand jury indicted Mr Kohberger on the charges, paving the way for the case to proceed without and leading to the cancellation of the preliminary hearing.

Mr Kohberger is accused of breaking into the student home in the early hours of 13 November and stabbing the four students to death in a horror attack that rocked the college town of Moscow and sent shockwaves across America.

The motive remains unknown and it is still unclear what connection the WSU PhD student had to the University of Idaho students – if any – prior to the murders.

However, the affidavit, released in January, revealed that Mr Kohberger’s DNA was found on a knife sheath left behind at the scene of the murders.

It also revealed that his white Hyundai Elantra was caught on surveillance footage at the crime scene and that one of the surviving roommates came face to face with the killer – masked, dressed in head to toe black and with bushy eyebrows – as he left the home in the aftermath of the murders.

Xana Kernodle and Ethan Chapin (Jazzmin Kernodle)

New details have also emerged about what was found during an initial search of his apartment and a rental storage unit.

The court documents show that two items found in his apartment tested positive for blood.

The two items were a mattress cover on the bed and an uncased pillow, both of which had visible “reddish brown stains”.

The documents do not reveal who the blood belongs to.

Investigators seized a string of other items from his home including possible human and animal hair strands, a disposable glove and a computer.

The murder weapon – a fixed-blade knife – has still never been found.

As a criminal justice PhD student at WSU, Mr Kohberger lived just 15 minutes from the victims over the Idaho-Washington border in Pullman. He had moved there from Pennsylvania and began his studies there that summer, having just completed his first semester before his arrest.

Before this, he studied criminology at DeSales University – first as an undergraduate and then finishing his graduate studies in June 2022.

Madison Mogen and Kaylee Goncalves pictured together before their murders (Instagram)

While there, he studied under renowned forensic psychologist Katherine Ramsland who interviewed the BTK serial killer and co-wrote the book Confession of a Serial Killer: The Untold Story of Dennis Rader, the BTK Killer with him.

He also carried out a research project “to understand how emotions and psychological traits influence decision-making when committing a crime”.

Now, he is facing life in prison or the death penalty for the murders that have rocked the small college town of Moscow and hit headlines around the globe.