Brian Laundrie's sister Cassie has urged her fugitive brother to 'come forward' and turn himself in, saying she doesn't know 'what to think' about what happened on his doomed cross-country trip with fiancee Gabby Petito.
'I really wish he had come to me first that day with the van because I don't think we'd be here,' she said.
Cassie said she is feeling a mix of emotions as her brother is still on the run after more than two weeks while Petito's death is being investigated as a homicide.
'I worry about him, I hope he's ok and I'm angry I don't know what to think,' she said.
'I would tell my brother to just come forward and get us out of this horrible mess.'
Laundrie's sister has come under fire in recent days after it emerged she had seen her brother twice in the time between him returning home to Florida and going on the run - despite previously claiming she hadn't spoken to him.
She was seen confronting a group of protesters outside her home on Monday, telling them she was 'livid' at her parent's lawyer Steve Bertolino for telling the press about the holes in her version of events.
Brian Laundrie's sister Cassie has urged her fugitive brother to 'come forward' and turn himself in, saying she doesn't know 'what to think' happened on his doomed cross-country trip
Brian Laundrie and Gabby Petito in an Instagram photo on their cross-country trip on June 26. Cassie told ABC's GMA she wished her brother had come to her first when he returned home without Petito 'because I don't think we'd be here' if he did
In the exclusive interview with GMA, airing Tuesday morning, Cassie insisted she does not know where her brother - who has been named a person of interest in Petito's death - is and claimed she has cooperated with investigators since 'day one'.
She defended the fact she had seen her brother on his return from his and Petito's campervan adventure, claiming she 'didn't pick up on anything' and they were just 'ordinary' visits - despite Petito not being present and her brother not being expected to return home for at least another month.
Cassie said her brother and parents had stopped by the home she shares with her husband and two sons for an 'ordinary' visit on September 1 - the day he returned.
She then saw him for a second - and last - time on September 6 when she visited him and their parents at Fort De Soto Park, where the trio were camping.
'We just went for a couple of hours and we ate dinner and had s'mores around the campfire and left, and there was nothing peculiar about it,' she said.
'There was no feeling of grand goodbye. There was no nothing.'
'I'm frustrated that, in hindsight, I didn't pick up on anything,' she added, insisting 'it was just a regular visit.'
She claimed she has not heard from her brother since and that if she knew where he was she would 'turn him in.'
While she insisted she had nothing to do with his disappearance, she admitted she wasn't so sure about her parents who she urged to cooperate with investigators.
When Petito was reported missing on September 11, Christopher and Roberta Laundrie refused to let authorities speak to their son.
They then didn't tell police he had vanished until three days after they allegedly last saw him on September 14, sparking a nationwide manhunt.
Questions continue to mount about what Laundrie's parents know about the doomed cross-country trip and their son's current whereabouts with rumors circulating that both Laundrie and his mom have been using burner phones.
'I don't know if my parents are involved,' said Cassie. 'I think if they are, then they should come clean.'
Cassie said she is concerned for her brother, who wouldn't normally go missing for so long.
Cassie was seen with her husband James Luycx outside her home on October 4 where she confronted a group of protesters
However, she also said she 'want[s] answers' about what happened to Petito, who she previously described as 'like a sister.'
'I hope my brother is alive because I want answers just as much as everybody else,' she said.
While she said she had never seen any signs of domestic violence between the young couple, she admitted it was 'pretty typical of them to argue and try and take space from each other.'
Cassie told GMA she believes Petito's family 'deserve answers' and that she wants them to know she is thinking of them.
Cassie is to date the only member of the Laundrie family - including Laundrie himself - who has spoken publicly about Petito's disappearance and death.
She claimed in an interview with ABC's Good Morning America on September 17 - two days before Petito's body was found in Wyoming - that she had not spoken to her brother since September 1 and that she 'wish[ed] I had more information' to give investigators.
'I haven't been able to talk to him. I wish I could talk to him,' Cassie said at the time. 'I've cooperated in every way that I can. I wish I had information or I would give more.'
Cassie also described Petito as 'like a sister' to her and said she and her family 'want Gabby to be found safe.'
'Obviously me and my family want Gabby to be found safe,' she said. 'She's like a sister and my children love her, and all I want is for her to come home safe and found and this to be just a big misunderstanding.'
Brian's sister said that she is 'livid' at her parent's lawyer Steve Bertolino, who told the press Friday that Cassie saw her brother twice since Petito's disappearance – on September 1 and 6 – despite her saying otherwise in a previous interview
But her version of events unraveled Friday, when Dog the Bounty Hunter - who joined the manhunt for Laundrie Saturday - revealed he had received a tip about Cassie joining her brother and parents at the Fort De Soto Park campsite five days after she claimed they had their last alleged encounter.
The Laundrie family lawyer confirmed on Friday that Cassie Laundrie saw her brother on September 1 when he came by her house - the same day he arrived back from the couple's cross-country van trip alone.
Cassie saw him again on September 6 during a family camping trip