Chapman chastised Laundrie's parents, saying they "need to be doing more to signal Brian to stop running."
"I can't fathom how Brian's parents can live with themselves," he said.
Chapman said that the coroner's report, along with evidence that Laundrie reportedly called his parents near the area where Petito's body was discovered, shows that is likely responsible for Petito's death.
"The coroner's statement has established a timeline that looks worse for Brian Laundrie," Chapman said.
Authorities have not named Laundrie as a suspect in Petito's death. However, they do consider him a person of interest in the case. He is currently wanted on a federal warrant for using a debit card without permission.
"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," the Laundrie's family attorney Steve Bertolino said in a statement. "At this time, Brian is still missing, and when he is located, we will address the pending fraud charge against him."