The horrifying case of four University of Idaho students butchered in an off-campus home has taken another dramatic twist after it emerged that the parents of their accused killer are testifying in a separate case thousands of miles away in Pennsylvania.

In a bombshell development this week, it emerged that Bryan Kohberger’s parents have been subpoenaed to appear before a grand jury investigating the disappearance and death of mother-of-three Dana Smithers.

Smithers, 45, was last seen alive in May 2022.

Her remains were finally discovered last month with her cause of death still a mystery.

It remains unclear what connection – if any – her disappearance and death may have to Mr Kohberger, who was living close to Smithers at the time she vanished.

But multiple reports have revealed that Mr Kohberger’s parents Michael and Maryann Kohberger have been ordered to testify in the case.

A source told CNN that the accused killer’s mother has already given evidence to the grand jury while his father is expected to testify on Thursday.

Any information in the case can then be turned over to prosecutors in Idaho who have charged Mr Kohberger with the quadruple murders of Kaylee Goncalves, 21, Madison Mogen, 21, Xana Kernodle, 20, and Ethan Chapin, 20.

So who was Dana Smithers and what happened to her?

Mysterious disappearance

In May 2022, Smithers vanished without a trace back from Monroe County – the same county in Pennsylvania where Mr Kohberger was living at the time before moving cross-country to Washington state in the summer to pursue a graduate degree program in criminal justice.

A ring video camera captured Smithers leaving a neighbour’s house at around 11.05pm on the night of 28 May, holding her cellphone in her hand.

She was never seen alive again.

What was especially odd was that Smithers’ cellphone, wallet and daily medication were all found at her home.

Earlier that day, Smithers and her youngest daughter, 7, had gone to a local festival at the Happy Hour Bar and Grille in Stroudsburg with her daughter’s father.

Smithers’ sister Stacey told NBC’s Dateline in December that the former couple were no longer together but were still on good terms.

At the festival, Smithers appeared to be havinga good time, dancing and saying hello to people.

The three returned to the home that Smithers, her daugher and Smithers’ mother shared.

Later that night, Tara Cioni said that Smithers called into her home to hang out. The two women lived just a couple of doors down from each other and were good friends so would often just call in to see each other on an evening.

“We’re best friends. She’s been my neighbor for 16 years. We’ve raised our children together,” Ms Cioni told Dateline.

“It was an open door policy, like, with her. So she came in and she was here for a little bit.”

Ms Cioni said that, in hindsight, she wonders if something was troubling her friend that night.

Smithers – who had a history of substance abuse – was smoking, something she only did if she was “nervous” or on edge.

Ms Cioni said that Smithers asked her to come back to her house to hang out but she was tired so said she was going to bed.

That was the last time she saw her.

“If I would have known that was the last time I would have seen her, I would have definitely asked more questions but I was sort of like, ‘I’m going to bed,’” she said.

Looking back, she said that she doesn’t think Smithers could have been using drugs again.

“I really don’t think it was that,” she said.

Her sister added that Smithers had her medication adjusted recently and appeared to be “getting much better” at the time,

The following morning, Smithers’ mother realised her daughter had not come home.

Initially, the family wasn’t too concerned as Stacey said the 45-year-old had stayed out all night in the past.

But, when she didn’t show up for Memorial Day celebrations with the family on 30 May, they knew something was wrong.

Smithers and her children, aged 25, 23 and 7, had a family tradition to go to Knoebels Park in Pennsylvania ever Memorial Day.

“She would not have missed Memorial Day,” said Stacey, adding that she would also never have left her youngest child for that long.

“She didn’t do anything that didn’t involve her kids,” she said.

“That was her thing. I mean she was always there with the kids.”

She was reported missing days later after Stacey said law enforcement initially didn’t take her disappearance seriously.

In June, the Pennsylvania State Police and local police carried out searches with cadaver dogs at Glen Park in Stroudsburg – a heavily wooded area close to her home. The search did not turn up anything and the case appeared to go cold for months.

A missing persons report described her as a 45-year-old white female, 5 foot 5 inches, approximately 165 pounds, with brown eyes, brown hair and last seen wearing black jeans with a burgundy shirt.

For almost a year, the mother-of-three’s family desperately searched for answers and Smither’s case featured in an episode of NBC’s Dateline in December 2022 – one month after the four students were murdered in Idaho.

Stacey feared the worst, saying: “I think something happened. I don’t think she’s here anymore.”

Remains found

Almost one year later – on 27 April – Smithers’ remains were found in a wooded area in Stroudsburg.

Stroud Area Regional Police said that a Borough employee had discovered decomposing human remains in a wooded area close to Park Avenue in the Borough of Stroudsburg.

Due to extensive decomposition, the gender and identity of the individual was unclear at the time.

Using dental records, the remains were later identified as belonging to Smithers.

Her cause and manner of death is not yet known.

What is Bryan Kohberger’s connection to the case?

Despite the bombshell development, Mr Kohberger has a solid alibi for Smither’s disappearance and is likely not connected, a source told Eyewitness News.

The grand jury investigation is still ongoing.

It is not clear what the Mr Kohberger’s parents Michael and Maryann Kohberger are being asked in connection to the case.

However, it comes following a report that one of the accused killer’s older sisters grew increasingly suspicious that her brother could have been involved in the Idaho murders prior to his arrest.

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 when the family gathered to spend the holidays together back in Pennsylvania, sources told NBC’s Dateline.

In the Smithers’ case, a lawyer for Mr Kohberger’s parents tried unsuccessfully to have the subpoenas cancelled, the source told CNN.

Pennsylvania judges will then be permitted to share transcripts of the grand jury witness testimony with law enforcement agencies across the country in Idaho.