Brian Laundrie Update: Cassie Knows More About Brother's Disappearance, Dog The Bounty Hunter Claims

Reality television personality Duane Chapman visited Brian Laundrie's sister Cassie Laundrie's house in Florida amid the ongoing manhunt for her brother.

Chapman – also known as Dog the Bounty Hunter – knocked on Cassie's front door repeatedly as he wanted to speak to her, TMZ reported. However, no one answered the door, following which Chapman told the media at the scene he knows Cassie has information about Brian's disappearance. He also added he thinks she is a vital person with whom he should speak to determine Brian's whereabouts.

Earlier this month, Cassie had spoken to the media saying that she doesn't have the slightest clue where Brian was hiding. She also said she doesn't know if her parents were involved in any way in the case.

"We are just as upset, frustrated and heartbroken as everyone else," Cassie said, while talking to protesters outside her home in Florida.

The search for Gabby Petito's ex-fiancé has entered the fourth week after a warrant was issued against him for illegally using the former’s credit card to make a purchase or withdraw $1,000 between Aug. 30 and Sept.1.

Petito’s body was found on Sept. 19 at a national park in Wyoming, at least three weeks after the coroner estimated she was killed. The coroner Tuesday ruled the cause of her death to be strangulation.

Following the autopsy report's release, Brian's family attorney stressed he was only a person of interest in the case.

"Gabby Petito’s death at such a young age is a tragedy. While Brian Laundrie is currently charged with the unauthorized use of a debit card belonging to Gabby, Brian is only considered a person of interest in relation to Gabby Petito’s demise," Steve Bertolino said in a statement to media. "At this time Brian is still missing and when he is located we will address the pending fraud charge against him."

While there is no evidence to prove if Brian is alive or dead, experts say that it would really take a lot for him to survive this long in the wilderness. An investigation expert has also pointed out the key evidence in obtaining a conviction in Petito's case could be present in her 2012 white Ford Transit van.