The sister of has doubled down on her assertion she has no idea where he is, as authorities search for him after the death of his fiancée Gabby Petito.
"No, I do not know where Brian is. ... I'd turn him in," Cassie Laundrie said in an exclusive that aired Tuesday.
Cassie Laundrie said if she could talk to her brother, she would tell him to come forward.
"I worry about him. I hope he's OK, and then I am angry and don't know what to think. ... I would tell my brother to just come forward and get us out of this horrible mess," she said.
Petito was found dead September 19 in a national forest in Wyoming, 18 days after authorities say Brian Laundrie returned to his parents' Florida home without her following a cross-country trip the pair took this summer.
After Petito's family reported her missing September 11, Laundrie left the Florida home September 14 and hasn't been seen since, his parents told authorities.
Though authorities have not explicitly connected Laundrie to Petito's death, they are looking for him, in part over a accusing him of illegally using another person's debit card.
Sister says she last saw her brother September 6 on camping trip
Cassie Laundrie said the last time she saw her brother was during a -- days before Petito's family reported her missing. The trip happened September 6-8, and the site is about 75 miles from where the Laundries' parents live, county officials have said.
Cassie Laundrie told ABC she last saw and spoke to him September 6.
"We just went for a couple of hours and we ate dinner and had s'mores around the campfire and left. There was nothing peculiar about it. There was no feeling of grand goodbye. There was no nothing," Cassie said of her last encounter with her brother, later adding she was "frustrated" she didn't pick up on anything.
"It was just a regular visit," she said.
The-CNN-Wire
� & © 2021 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.
