(NewsNation) — On the Long Island street where Rex Heuermann lived, neighbors are grappling with the reality that a serial killer could have been living in their midst.

Dominick Cancellieri, who lived next door to Heuermann for 15 years, recalls some very strange behavior over the years, including Heuermann burning garbage, digging holes in the backyard and fighting over a parking spot.

“It seemed to be like once every few weeks, I would smell garbage burning at his house,” Cancellieri said Thursday on “CUOMO.”

Heuermann, 59, has been charged in connection with the deaths of three women whose bodies were found in 2010 and 2011 along a stretch of highway on Long Island’s Gilgo Beach. He’s the lead suspect in a fourth death. All of the women were sex workers and were found wrapped in burlap sacks.

Police continue to search his home in Massapequa Park, and were seen Thursday repositioning squad cars in an apparent attempt to obstruct the view of reporters. Authorities are also active in South Carolina, where Heuermann owns property.

Since Heuermann’s arrest, neighbors and others who knew him have shed more light on his behavior and demeanor.

In one instance years ago, Cancellieri remembers hearing digging coming from Heuermann’s backyard.

“I really wanted to go and check out what it was and look through the fence, but something stopped myself from doing it,” Cancellieri said. “Now, with everything coming to fruition, it doesn’t surprise me in the slightest bit.”

Cancellieri says he didn’t talk to Heuermann that much, but they did have one run-in when Cancellieri says Heuermann parked his truck halfway into his parking spot.

“I said to him, ‘Listen, you’ve got to move your car,’ and he got a little loud, I got a little loud back with him, and he ended up finally moving his car, but every instance, even just the way he looked, I always thought this guy was a weirdo,” Cancellieri said.

Police say Heuermann had seven burner phones and also used the phone of one of the victims to call and taunt her family.

He has pleaded not guilty to three charges of first-degree murder and three charges of second-degree murder in the deaths of Melissa Barthelemy, Megan Waterman and Amber Costello. Authorities are continuing to work toward charging him for the death of Maureen Brainard-Barnes.

Heuermann’s attorney has denied the murder allegations and said the evidence made public at this point is circumstantial.