Duane "Dog the Bounty Hunter" Chapman said he "absolutely" believes the the sister of Brian Laundrie -- the fiancé of Gabrielle 'Gabby' Petito and a person of interest in her death -- knows where her brother is.
TMZ shared video footage of Chapman and his wife, Francie, knocking on the door at Cassie's home in Lakewood Ranch, Florida to no answer just before 7:30 p.m. on Wednesday (October 13).
When asked by the person recording if he thinks Cassie is knows more about her brother's whereabouts than she's admitting, Chapman said, "absolutely."
Earlier this month, Cassie Laundrie told ABC News that she didn't know where her was and would "turn him in" if she did, which she reiterated to protesters outside her Florida home in a video shared by TMZ.
Cassie Laundrie said she last heard from her brother on September 6 -- after he returned from his cross country trip without Petito -- when the family went to Fort De Soto Park in Pinellas County, Florida.
"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. "It was just a regular visit."
Cassie added that it's unusual for Brian to disappear this long, having initially been reported missing on September 17, days after Petito's parents initially reported her missing.
"I worry about him. I hope he's OK, and then I'm angry and I don't know what to think," she said. "I hope my brother is alive because I want answers just as much as everybody else."
Cassie said she's cooperated with authorities during their investigation "since day one" and believes her parents should do the same, noting that she's unsure of their role.
"I don't know if my parents are involved," she said. "I think if they are, then they should come clean."
Laundrie's parents claim the 23-year-old was last seen hiking in Carlton Reserve on September 13 after he returned to Florida from a cross country trip without Petito.
On Monday (October 11), Chapman told the Sun that he not only thinks Laundrie -- who has not been charged in the case -- killed Petito, but also called his parents at the scene of her death, who he believes advised him to return to their home in Florida.
"Of course he murdered her. I think he called the mom and dad right from the scene and said 'omg.' Now we have to remember that they lived -- Gabby and Brian -- with his mom and dad for almost two years," Chapman said while piecing together how he believes an alleged phone call between Brian Laundrie and his parents, Chris and Roberta Laundrie, sounded. "And the house, I was there, it’s not a huge house so I’m sure they heard, the parents probably heard Gabby screaming. I was told by a very close source that he was a gentleman.
"I think he said, 'mom, she was screaming, she was screaming so I put my hand over her mouth, and I held my hand and she was screaming and when I took it away she wasn’t breathing and I tried CPR'."
On Tuesday (October 12), Teton County Coroner Dr. Brent Blue -- who performed an autopsy on Petito -- announced her death was ruled as a death by strangulation and the manner of death to be a homicide during a press conference on Tuesday (October 12).
Dr. Blue said Petito's death is believed to have occurred 3-4 weeks prior to her remains being found on September 19 and confirmed to match her days later.
Dr. Blue confirmed the ruling was made while working alongside local and federal authorities. No other information will be released in adherence with state law.
Laundrie is currently at the center of a publicized search by the Federal Bureau of Investigation and local authorities at the Carlton Reserve campsite in Venice, Florida.
Dr. Blue said local law enforcement would decide who would be charged in connection to Petito's homicide case.
On October 7, Chris Laundrie joined authorities in their search of Carlton Reserve for his son, according to family attorney Steven Bertolino.
Remnants of a campsite that appeared to have been recently used were reportedly the focus of the search, a source close to the Laundrie family told CNN's Chris Cuomo last Wednesday (October 6).
On September 30, police released additional bodycam footage which shows Petito telling an officer that an argument with Laundrie got physical.
The newer footage stems from the incident on August 12 in Moab, Utah in which police made contact with Petito and Laundrie after a bystander called the Moab Police Department and reported seeing a man hitting a woman.
Officers pulled over the van Laundrie and Petito were traveling in on their cross-country trip and Petito told officers that she intially slapped Laundrie before he retaliated.
"I guess, but I hit him first," Petito said when asked by an officer if Laundrie hit her in the face.
"Where did he hit you? Don’t worry. Just be honest," the officer asked.
"Well, he grabbed my face," Petito said.
"Did he slap your face? Or what?" the officer responded.
"Well like, yeah he grabbed me with his nail, and I guess that’s why I definitely have a cut right here because I can feel it when I touch it, it burns," she said, while holding her jaw and crying.
The video then shows Laundrie recanting his side of the incident.
"She gets really worked up, and when she does she swings, and she had her cellphone in her hand, so I was just trying to push her away," Laundrie said.
The new video adds to previously released bodycam footage showing the couple addressing the incident with police, which an officer described as a mental health crisis, not a domestic assault, according to a police report.
The city of Moab announced on September 28 an independent investigation will be conducted on officers' handling of the situation involving Petito and Laundrie.
Last month, an arrest warrant was issued for Laundrie after a grand jury indicited him for his "use of unauthorized devices" during the events following the death of Petito.
The indictment obtained by CNN accuses Laundrie of using a debit card and PIN number for accounts that didn't belong to him between August 30 to September 1 in order to make purchases totaling more than $1,000.
A source close to Laundrie's family told CNN the 23-year-old left his own wallet and cell phone behind when he was last seen leaving his parents' Florida home 10 days ago after he initially returned to the area from a cross-country road trip without Petito, who was reported missing on September 11.
The source added that Laundrie's parents were concerned he might harm himself at the time he left their home.
An attorney for Laundrie's family emphasized that the arrest warrant isn't related specifically to Petito's death, rather incidents committed by Laundrie afterward.
"It is my understanding that the arrest warrant for Brian Laundrie is related to activities occurring after the death of Gabby Petito and not related to her actual demise," Steve Bertolino said in a statement. "The FBI is focusing on locating Brian and when that occurs the specifics of the charges covered under the indictment will be addressed in the proper forum."
"While this warrant allows law enforcement to arrest Mr. Laundrie, the FBI and our partners across the country continue to investigate the facts and circumstances of Ms. Petito's homicide," added FBI Special Agent in Charge Michael Schneider. "We urge individuals with knowledge of Mr. Laundrie's role in this matter or his current whereabouts to contact the FBI."
On September 24, local and federal authorities continued to search for Laundrie in the Carlton Reserve, a nature preserve estimated to be around 25,000 acres, in North Port near his family home after pausing September 23 due to darkness.
Chapman has inserted himself into the search for Laundrie and told TMZ last Monday (October 4) that he believes Laundrie is "alive" but not "doing well."
Chapman said Laundrie showed "no evidence" of being suicidal and credited Laundrie's social media presence for his theory.
"If you go to his Instagram pages and look what kind of person he really is and the books that he reads and especially a very favorite book, that's not books for sucidal people," Chapman said.
On October 3, Chapman tweeted a video update of himself wading through the Florida swamp waters in search for Laundrie.