Police say they have a massive amount of potential evidence to go through following a 12-day search at the suspected Gilgo Beach serial killer's home.

The crime scene at Rex Heuermann's Massapequa Park house closed Tuesday afternoon.

LIVE BLOG: Gilgo Beach Murders

Attorney Fred Klein is not involved directly in the case. But he says investigators will now have to search each item they took out and possibly do forensic testing on it.

He says the items that could be the most beneficial are anything that could provide a DNA sample or belongings from the victims.

"Clothes, jewelry, identification cards, preferably with their photographs on them - serial killers are known to keep these items helps them relive the pleasure of the killing," Klein says.

MORE: Suffolk DA: Search of accused Gilgo Beach serial killer's home ends, massive amount of material taken

Canines assisted in the investigation at Heuermann's home and they could possibly be used again, according to Mike Gould, former lieutenant and commanding officer of the police K-9 Unit.

Gould says dogs could be seen at other locations across Long Island like Gilgo Beach as the investigation continues.

"There come to a point of diminishing returns," Gould says. "Everything degrades so in 100 years from now there is not gonna be any odor so there's a fine point when a dog can actually detect an odor.”

WATCH: DOCUMENTARY AND BACKGROUND INFORMATION - Gilgo Beach: Unsolved

Klein says digging is not routine even in a homicide investigation so he believes there was some additional evidence that gave them probable cause to look into the backyard of the home.