The investigation into the home of alleged Gilgo Beach killer, Rex Heuermann, took a major turn this weekend. Police moved their extensive search from inside his Massapequa Park home to the backyard.

From cadaver dogs, to ground penetrating radar (GPR) equipment and digging up Heuermann’s backyard, authorities are literally leaving no stone unturned. Investigators only have one chance to gather all the evidence they need from the property, according to experts.

“Once they collect that evidence, they can’t close that scene and then go back because evidence might be destroyed,” said Michael Alcazar, retired NYPD detective and adjunct professor at John Jay College of Criminal Justice.

LIVE BLOG: Gilgo Beach Murders

Police investigated Heuermann for more than a year before his arrest. Now, their investigation is ramping up. Detectives can interview people close to him, including neighbors and family members.

News 12 was the first to report that the investigation moved from collecting evidence from inside the Massapequa Park home, to searching for clues in his backyard.

“They’re kind of like detective archeologists, right? They had cadaver dogs so maybe they're looking for possible human remains and they don't want to disturb it or destroy it,” explained Alcazar. “They use the GPR to identify where this evidence may be. It could search for metal. It could search for solid objects. I mean, it could be skeletal remains. It can detect all that. It’s pretty good technology to help the police.”

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Suffolk County Police Commissioner Rodney Harrison said the search of the Nassau County home may wrap up this week. Evidence technicians have been scouring the property for 11 consecutive days.