The mother of two missing children has failed to bring the kids to the authorities by a Thursday night deadline.

Lori Vallow was court-ordered to bring her children - Joshua 'J.J.' Vallow and Tylee Ryan - to the Rexburg Police Department or to the Department of Health and Welfare by 5pm Thursday.

But there was no sign of her or the youngsters who have been missing since September, sparking questions over whether they are still alive.

Lori and her new husband Chad Daybell were found in Kaua'i over the weekend, two months after they fled Idaho when police began asking questions regarding the whereabouts of her children, who were last seen in September.

The couple were served with two search warrants and the court order to produce the children after authorities concluded there was no evidence that J.J. and Tylee were ever in Hawaii with their mother.

The case captured national attention when it was revealed that police were also investigating a string of deaths surrounding Lori and Chad, who family members say are members of a dangerous doomsday cult.

Cops in Idaho have frequently said the pair are not cooperating with police and have re-opened an investigation into the death into Chad's first wife Tammy.

At a press conference Thursday after the deadline passed, JJ's grandmother, Kay Woodcock admitted she doesn't know what will happen next and was asked what punishment she thinks Vallow deserves.

Kay and Larry Woodcock made a final desperate plea for the safe return of their grandson Joshua 'J.J.' Vallow hours before his mother, Lori Vallow, faces a deadline to physically produce the boy and his sister, Tylee Ryan, to authorities in Rexburg, Idaho

Seven-year-old J.J. and 17-year-old Tylee were last seen in Rexburg in September

Lori and her new husband Chad Daybell have been living in Princeville, Hawaii, since mid-December after fleeing Idaho when police began asking questions about where her children were. The couple were seen for the first time since news of her children's disappearance captured national attention in a video recorded after they were served with search warrants in Kaua'i on Sunday (pictured)

She said: 'What exactly that is, I don't know. I can't guess on it, I can't say for sure whats going to happen next.

'I'd love to know where those kids are and I think all of America wants to know where they are,'I think all of this is beyond crazy.

'How do you not know where your child is? How do you not have them for four months?'

Kay Woodcock traveled to Rexburg from Arizona ahead of the deadline as they cling to hope that they will receive confirmation that the children are alive.

'I just want those kids back! Please show us where those kids are,' Larry told CBS5 on Wednesday. 'Please tell me. I'll go get them. And I don't care where they're at. I'll go get them.'

Larry and Kay said they weren't optimistic that Lori would show in Idaho - even though she now faces arrest.

'She's got all the attention on her - good, bad or indifferent - and it's going to be bad if she doesn't show up,' Kay said.

'Do I believe? Yes, I want to believe that [she will],' Larry said in a different interview with ABC News. 'Do I think that she's going to bring them? Honestly, no.'

'Nothing with Lori right now makes sense,' he said, adding that the Lori he's known for the past 12 years 'is not the same person that is here on Earth today'.

The family will continue their fight to find J.J. and Tylee.

'We're in this for the long haul,' Larry said. 'This is not going to end tomorrow. I'm not going to let it end. Kay is not going to let it end. Our family is not going to let this end.'

Timeline of Joshua and Tylee's disappearance July 11: Lori Vallow's husband, Charles Vallow, killed in self-defense by her brother, Alex Cox, in Arizona following an argument between the three people August: The last time Joshua's grandparents, Kay and Larry Woodcock, said they saw the boy via FaceTime August: September: Lori moved children Joshua and Tylee to Rexburg, Idaho September 23: The last time Joshua was seen at his school in Idaho October: Activity found on a Venmo account that may belong to Tylee October 19: Chad Daybell's wife, Tammy Daybell, dies at their home in Rexburg. Officials rule her death to be of natural causes October 22: Tammy is buried in Springville, Utah October 25: A friend of Tylee receives a text from her phone Early November: Lori and Chad get married November 26: Out-of-state relatives ask Idaho police to perform a welfare check on Joshua. Lori and Chad claim he is in Arizona with a family friend. Police also learn Tylee has not been seen since September, either November 27: Police execute a search warrant at Lori and Chad's home, discovering the couple have fled the city December 11: Tammy Daybell's body is exhumed from the Utah cemetery December 12: Lori's brother, Alex Cox, believed to have died in Arizona December 21: Rexburg police issue a press release about J.J. and Tylee, revealing they believe the children's disappearance is linked to the death of Tammy Daybell December 24: Lori and Chad issue a statement through an attorney saying they love their son and daughter and look forward to addressing 'allegations once they have moved beyond speculation and rumor' December 30: Police accuse Lori and Chad of lying to investigators and say they believe the couple know where the children are or what happened to them January 26: Lori and Chad are seen for the first time in months as police serve two search warrants in Kaua'i Advertisement

J.J. and Tylee were last seen in Rexburg on September 23 but were never reported missing by their mother.

Authorities began searching for the children after performing a welfare check on November 26 ordered by concerned relatives who said they hadn't spoken to J.J., who is autistic, in months.

When officers returned the following day, they found that Lori and Chad - who tied the knot early that month - had fled from the home.

Authorities say the couple have repeatedly lied about where J.J. and Tylee are and refused to cooperate with the investigation.

Lori and Chad were labeled persons of interest as investigators said they believe the mother knows where her children are or what happened to them.

'We strongly believe that Joshua and Tylee's lives are in danger,' Rexburg police said last month.

The case captured national attention with the revelations that police were also investigating a string of deaths surrounding Lori and Chad, who family members say are members of a dangerous doomsday cult.

The first death is that of Lori's estranged husband and J.J.'s adoptive father Charles Vallow, who was shot dead by her brother Alex Cox in Arizona on July 10.

Charles and Lori had gotten into an argument when the father came to pick up J.J. at the mother's home in Chandler.

Police initially determined that Cox acted in self defense while intervening in an argument between Charles and Lori. But the case was reopened amid the multi-state search for J.J. and Tylee, who had moved to Idaho with their mother a month after the shooting.

The second mysterious death was Tammy Daybell - Chad's previous wife - who was found dead at the couple's home in Salem, Idaho, on October 19.

She was originally believed to have died of natural causes, but was later deemed suspicious as police investigating J.J. and Tylee's disappearance learned that Chad had tied the knot with Lori just two weeks after Tammy's death.

Tammy's body was exhumed on December 11 and the autopsy results have not yet been released.

On December 12, Lori's brother, Alex Cox, was found dead in Gilbert, Arizona.

The 51-year-old's death is now under investigation as police wait for an autopsy to determine the cause.

Lori's estranged husband Charles Vallow (pictured together) was shot dead by her brother, Alex Cox, in July

Chad's then-wife Tammy Daybell (pictured together) was found dead under mysterious circumstances in October, just two weeks before he married Lori

As police worked to untangle the troubling mystery, Lori and Chad were sunning themselves in Princeville, Hawaii, where they've reportedly been renting a home since mid-December.

Authorities say they had known for some time that the couple were in Hawaii, where Lori lived with Charles a few years back. Their whereabouts became public on Sunday when officers served them with search warrants for their car and the townhome.

A reporter for the East Idaho News, who had received a tip about the search warrants the day before, approached the couple in the parking lot after the police confrontation.

Lori and Chad stayed silent and kept walking as the reporter, Nate Eaton, repeatedly asked them where the children are and if they are alive.

The mother only spoke once after the reporter said that people eastern Idaho and across the country are praying for J.J. and Tylee.

'That's great,' she replied.

No charges have been filed against Lori or Chad and no warrants have been issued for the arrests.

That could change if Lori fails to comply with the court order to produce her children to authorities in Idaho on Thursday, which could result in her facing a contempt of court charge and possible arrest and extradition from Hawaii.

The Rexburg Police Department, which is leading the investigation with assistance from Kaua'i and federal authorities, has refused to elaborate on what will happen if Lori doesn't show in Idaho because the case remains sealed and confidential.

An attorney for Lori and Chad issued on their behalf last month, saying they love their son and daughter and look forward to addressing 'allegations once they have moved beyond speculation and rumor'.

Police served Lori and Chad with two search warrants on Sunday in Kaua'i

Officers are seen confronting the couple next to their SUV in a resort parking lot

Lori and Chad stayed silent as an East Idaho News reporter repeatedly asked them where the children are and if they are alive

The couple have reportedly been holed up in this three-bedroom condo at the Kaiulani of Princeville Townhomes in Princeville, Hawaii, since mid-December

Family members paint a dark portrait of Lori and her new husband

While police have been careful not to publicly cast suspicions on Lori and Chad, a troubling portrait of the pair has emerged from accounts from family members who claim they are members of a dangerous cult obsessed with the end of the world.

Kay Woodcock - the sister of Charles Vallow who is also J.J.'s grandmother - issued a statement in December in which she described how Lori turned into a 'monster' after she met Chad in 2017.

Chad, 51, is a prolific author of 25 books focusing on doomsday scenarios and near-death experiences. He is what's known as a 'prepper' - someone who is getting ready for the End of Times - and was a member of a group called Preparing a People.

Last month DailyMail.com exclusively revealed that Chad had been kicked out of the Church of Jesus Christ of Latter Day Saints back in the fall after he declared himself a prophet.

Lori reportedly began reading Chad's writing while she was living in Hawaii with Charles, J.J. and Tylee between 2014 and 2017.

It's unclear how or when exactly Lori and Chad met, but family members say it was sometime around June 2017.

The pair made their first appearance together in December 2017 on a podcast for Preparing a People, a group which, according to its website, organizes conferences and lectures for those who 'look forward to the rapidly coming changes to our current Telestial way of life, and rejoice in the hope of a far better world to soon come!'

Chad, 51, is a prolific author of 25 books focusing on doomsday scenarios and near-death experiences. He is seen at a signing for one of his books in May 2019

Lori and Charles' marriage crumbles as she strengthens her alleged cult ties

Lori and Charles' marriage deteriorated rapidly as she became more and more involved with Preparing a People, and he filed for divorce and for custody of J.J. in February 2019.

In court documents, Charles claimed that Lori - referred to as 'mother' - had recently become 'infatuated, at times obsessive, about near death experiences and spiritual visions'.

'Mother has told Father [Charles] that she is sealed [eternally married] to the ancient Book of Mormon prophet Moroni and that she has lived numerous lives on numerous planets prior to this current life,' the documents state.

'Mother also informed Father that she is a translated being who cannot taste death sent by God to lead the 144,000 into the Millennium.

'Mother believes that she is receiving spiritual revelations and visions to help her gather and prepare those chosen to live in the New Jerusalem after the Great War as prophesied in the book of Revelations.'

Charles Vallow (pictured) filed for divorce from Lori in February 2019

Charles also claimed in the petition that Lori had threatened to kill him.

During a January 29 phone conversation, Lori allegedly told Charles that she was a 'God assigned to carry out the work of the 144,000 at Christ's second coming in July 2020 and that if Father [Charles] got in her way of her mission she would murder him', the documents state.

Charles' sister Kay said she kept in close contact with him during the divorce proceedings, and that he would often call her in hysterics.

She said she suspected Lori and Chad were having an affair at the time and expressed concern over the fact that Lori's three previous husbands had died.

No information is known about Lori's first two husbands. Her third husband and Tylee's father, Joseph Ryan, died of an apparent heart attack in April 2018.

Earlier this month, Kay called Lori a 'black widow'.

'[Husband] three and [husband] four are dead. Five? He's next. How he's gonna go? I don't know. But I wouldn't sleep with my eyes closed,' she said.

Amid the divorce proceedings Charles was granted an order of protection against Lori - who he claimed had drained $35,000 out of their bank account.

When Charles tried to serve the order of protection to Lori, he couldn't find her. The family says she disappeared for nearly two months, leaving her children in relatives' care.

Charles revoked his petition for divorce about a month after filing it and moved to Texas.

Alex Cox (pictured) shot dead his sister Lori's estranged husband Charles in July 2019

Charles predicts Lori or her brother will kill him

Attorneys who represented Charles in the divorce spoke out earlier this month, claiming that their client had predicted either Lori or her brother Alex would kill him.

Lawyer Steven Ellsworth told FOX10 that Charles had told him: 'I'm afraid I'm gonna be killed, and I know who's gonna do it.

'I'm telling you, Steve, so that if something happens to me, I wanna make sure you let everyone know that something happens, I'm killed, that it's my wife Lori and her brother, Alex Cox.'

Five months later, his prediction came true.

Charles went to Lori's home in Chandler, Arizona, to pick up J.J. on July 10. When he arrived, the pair got into an argument that turned physical, according to Lori's brother Alex Cox.

Cox, who was visiting for the night, told police that he tried to intervene when Charles hit him in the back of the head with a baseball bat. He told investigators that he shot Charles twice in the chest to 'stop him'.

The Chandler Police Department recently released redacted body camera footage of Alex and Lori speaking to officers outside the home directly after the shooting.

Body camera footage shows Lori speaking to police after her brother shot dead her estranged husband at her home in Chandler, Arizona, on July 10, 2019

Lori calmly answered questions about her relationship with Charles, while Alex appeared much more frazzled as officers repeatedly had to ask him to repeat parts of the story.

He explained how the incident began when he tried to break up a fight between Charles and Lori, saying: '[Charles] told me not to interfere with them anymore or I'd pay.'

He claimed that his niece, Tylee, retrieved a baseball bat from her bedroom to protect her mother from Charles but that Charles grabbed it from her and started hitting him instead.

As he ran to his room to retrieve his gun, Lori and the children fled out of the home.

'I told him to put the bat down and he wouldn't,' Alex recounted.

'I said, 'I want you to put the bat tat down and he wouldn't. He came at me with the bat again so I shot him to stop him. That was it.'

Two family members and Charles' attorneys have disputed that account.

'We knew immediately that was wrong,' Charles' sister Kay said at a press conference this month. 'It was a setup.'

Charles' oldest son said he doesn't believe his father would have gotten violent with Lori or her brother.

'I knew my dad was the most passive person. He hated arguing with people. He'd never been in a fight, he was not an aggressive person in any way. I don't believe it at all,' the son told FOX10.

Lawyer Taylor Lawson told the outlet: 'We knew that this wasn't an accident. This wasn't self-defense.'

Lori uproots her family and follows Chad to Idaho

Within weeks of Charles' murder, Lori and her children moved to Idaho, where Chad lived.

Kay and Larry Woodcock said they were concerned as their contact with their grandson J.J. became much more limited. They last spoke to him over FaceTime in August.

Lori enrolled J.J. at Kennedy Elementary School on September 3. The last confirmed sighting of the boy was at the school on September 23. Principal Josh Wilson said Lori unenrolled him the following day, telling administrators she would be homeschooling him.

Tylee was also last seen on September 23, but it remains unclear where. Her last known communication, which has not been confirmed by authorities, took place over a month later.

A friend of Tylee's said she reached out to the 17-year-old on October 19 to say that she missed her and was thinking about her.

Six days later on October 25, the friend received a message from Tylee's phone which read: 'hi. miss you guys too ...luv ya.'

Within weeks of Charles' murder, Lori and her children moved to Idaho, where Chad lived

Relative accuses Lori's niece of trying to kill him in a drive-by shooting

Another alarming event linked to the case took place back in Arizona on October 2, when a relative of Lori's was targeted in a drive-by shooting.

Brandon Boudreaux, who was in the middle of a contentious divorce from Lori's niece Melani Boudreaux, was driving home from the gym in Gilbert when a bullet flew into his vehicle, missing his head by inches.

An ongoing police investigation revealed that the shooter was driving a Jeep registered to Charles Vallow.

Brandon believes his estranged wife and the mother of their four young children was behind the attempted murder.

He said his wife asked him for a divorce out of the blue over the summer after she joined Preparing a People with her aunt.

'I just don't know how people can get so wrapped up that they can end up in this space where these people are. It's just so radical, so different,' Brandon told The Arizona Republic last month.

Brandon Boudreaux was in the middle of a contentious divorce from Lori's niece Melani Boudreaux (pictured together) when he was targeted in a drive-by shooting in October

Chad's first wife Tammy Daybell dies under suspicious circumstances

Less than three weeks after the drive-by, Tammy Daybell was found dead at the home she shared with Chad in Salem, Idaho, on October 19.

An obituary stated that she passed away peacefully in her sleep.

Chad reportedly declined to have an autopsy performed and her cause of death was listed as natural. She was buried at Evergreen Cemetery in her hometown of Springville, Utah.

Just two weeks after his wife of 29 years died, Chad tied the knot with Lori on a quick trip to Hawaii.

A few weeks later, the Woodcocks contacted Rexburg authorities with concerns about Tylee and J.J., whom they hadn't heard from in months.

Police went to Lori and Chad's home on November 26, and the mother told the officers that J.J. was staying with relatives in Arizona, which turned out to be a lie.

They returned the following day and found that the couple vanished.

Investigators soon learned that no one had seen either of the children since September.

It later came to light that Lori had told friends that Tylee was dead and that she didn't have any minor children.

Tammy Daybell was found dead at the home she shared with Chad in Salem on October 19

The grave at Evergreen Cemetery in Springville, Utah, where Tammy's body was exhumed

The Daybells' home in Salem, Idaho, is pictured. Police searched the property on January 4

Rexburg police issue first statement on Tylee and J.J.'s disappearance

On December 21, the Rexburg Police Department issued a statement asking the public for information about the children's whereabouts.

They said there was reason to believe that their disappearance was linked to the death of Tammy Daybell, whose body had been exhumed on December 11.

Results of Tammy's autopsy results are still pending. Investigators have said they were testing her body for signs of poisoning.

A friend of Tammy's told DailyMail.com that the 49-year-old was training for a marathon at the time of her death.

'She was into healthy living, very fit — and then all of a sudden we hear she has died,' the friend said. 'It didn't make sense then and it doesn't make sense now.'

Chad also allegedly told a friend that he had visions about his wife's death three weeks before she died.

'He was emotionally distraught, he was crying and he said that his angels had told him that he was going to lose Tammy,' the friend, Tammy Rowe, told FOX13 of her concerning conversation with Chad.

Preparing a People removed all content from Chad and Lori from its website last month amid mounting speculation over the couple's possible involvement in J.J. and Tylee's disappearance and Tammy's death.

'We considered Chad Daybell a good friend, but have since learned of things we had no idea about,' the group's leaders, Nancy and Michael James, wrote in a post on the website that has since been removed. 'We recently learned of Chad's new marriage to Lori Vallow a couple weeks after Tammy Daybell died... We did not know Lori as well as we thought we knew Chad.

'We pray for the truth of whatever happened to be quickly manifest.'

Alex Cox dies under undisclosed circumstances

Cox, who had gotten married in early December, turned up dead the day after Tammy's body was exhumed.

Few details are known about the circumstances surrounding Cox's death as an autopsy is believed to still be underway.

It was later revealed that Cox had served time in prison in Texas for attacking Lori's third husband Joseph Ryan in 2007.

A warrant for Cox's arrest in Travis County, Texas, alleges that he had threatened to kill Ryan after the father exchanged custody of Tylee with Lori.

The warrant states that Cox followed Ryan into the parking lot to talk and then allegedly shocked him with a taser before the father escaped.

The following year, Alex pleaded guilty to a second-degree aggravated assault charge and served three months in jail.

Twelve years after the incident with Joseph - who died of an apparent heart attack aged 59 in 2018 - Alex killed Lori's next husband, Charles, in a similar custody exchange.

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Rexburg police slam Lori and Chad for refusing to cooperate

Nine days after their initial statement about the missing children, Rexburg police publicly slammed Lori and Chad for refusing to cooperate with the investigation.

'We know that the children are not with Lori and Chad Daybell and we also have information indicating that Lori knows either the location of the children or what has happened to them,' police said on December 30.

'Despite having this knowledge, she has refused to work with law enforcement to help us resolve this matter.

'It is astonishing that rather than work with law enforcement to help us locate her own children, Lori Vallow has chosen instead to leave the state with her new husband.

'We publicly call on Lori Vallow/Daybell and Chad Daybell to do the right thing and come forward with the information they have about the location and welfare of Joshua and Tylee. This entire investigation could have been avoided if Lori and Chad had simply been honest with law enforcement.'

The release also notes that in the weeks after Tammy's death, the couple told witnesses that Tylee had died in 2018 and that Lori had no minor children.

Police called those statements 'untrue', and said: 'We strongly believe that Joshua and Tylee's lives are in danger.'

Idaho sheriff brands the investigation a 'disaster'

Fremont County Sheriff Len Humphries, whose department is leading the investigation into Tammy's death, spoke exclusively to DailyMail.com around the time that Rexburg police issued their admonishment of Lori and Chad.

'From an investigation point of view this is a disaster,' Humphries said.

'There are multiple agencies involved — us, Rexburg police, the FBI, as well as police departments in Arizona.

'There are people who have died strangely in several places, and two kids that we have absolutely no idea where they are.

'Add to that, the mother is known to have told family members that her daughter died a year ago, which we know is not true.

'And then she claimed that the 17-year-old had run off with the seven-year-old and didn't say anything to authorities.

He added: 'What kind of parent doesn't help try to find their own kids when they are missing?'

Fremont County Sheriff Len Humphries, whose department is leading the investigation into Tammy's death, spoke exclusively to DailyMail.com around the time that Rexburg police issued their admonishment of Lori and Chad

Lori and Chad are located in Hawaii without their children

The case went quiet in the weeks following that interview - until it was revealed on Sunday that Lori and Chad had been located in Hawaii.

It is unclear what prompted authorities to seek search warrants after having known where the couple were for several weeks.

Investigators have not said what evidence they were looking for or whether they found anything substantial.

The news that the children were not with their mother was met with disappointment as well as renewed hope that maybe the truth could be nearing the surface as Lori was ordered to physically produce them to authorities.

The Woodcocks - who have offered a $20,000 reward for information that leads to J.J. and Tylee's return - are still clinging to hope that they're okay.

As for Lori, the grandparents say they are ready to be rid of her.

'I know that once we find those kids or this comes to an end, she'll never be in my life again,' Larry said Wednesday. 'She'll never be spoken of again. She'll just be trash going in the trash bin.'