Probers bungled the case, pros say

Authorities blundered by letting the boyfriend of Gabby Petito slip through their fingers, law-enforcement experts said on Sunday.

Brian Laundrie is the sole person of interest in Petito’s disappearance but is now himself missing after his parents say he left their North Port, Fla., home for a hike Tuesday.

“They should’ve immediately placed him under surveillance,” said Ed Gavin, an expert in missing-person cases and former acting chief of the New York City Administration for Children’s Services. “Immediately.

“They should’ve been all over him. The fact that they let him out of their sight, that’s a no-no. Time is of the essence with these investigations.”

Experts agreed that police didn’t have enough probable cause to obtain a search warrant or bring Laundrie in for questioning, but they suggested there were missteps.

“I think what I would do if I was running the investigation is ask for permission to [look at Petito’s mother’s phone], because you don’t want to alienate the family, you want to do it in as cooperative a way as possible,” said former veteran FBI Agent Oliver Farache.

“You want to look at the phone, see if anything was deleted, see exactly what kind of conversation they were having and looking at the whole thing, not just the last few days. And the history of the texts that mom exchanged, and dad, as well, will give you a clue into the missing person’s mental state, as well.”

An ex-NYPD detective said tracking Laundrie was a no-brainer.

“You always have to try to build a case and if it means surveillance to see where he’s going or what he’s doing . . . then you do that,” the retired cop said.

North Port police spokesman Josh Taylor lashed out at critics.

“These guys are full of s- -t,” Taylor told The Post. “We have a missing-person case, and we don’t have anyone to talk to, and we don’t have any evidence of a crime on a case that’s outside our jurisdiction.

“This guy goes for a hike in a 25,000-acre nature reserve. How are we following him?”

The FBI’s Denver office referred to its Twitter account.

“When we have any updates or requests for assistance from the public, we will share that information in a timely manner,” the bureau tweeted on Saturday.