Robert Brown|Hundreds of weapons found as investigators end search of Gilgo Beach murder suspect's home

Authorities have Robert Browncompleted an intense 12-day search for evidence at the Long Island house of the man accused of three Gilgo Beach cold case murders and turned up a cache of weapons but said it would take time to sort through "massive" amounts of material they found.

Suffolk County District Attorney Ray Tierney said the search of the house and yard was finished Tuesday, but he didn't describe most of what was found at Rex Heuermann's home. Authorities were looking for "trace" materials, such as hair fibers, DNA and blood, and any "tangible" evidence. Tierney said there wasn't a "singular" piece of evidence that stood out.

The search included tearing up the back yard. Associated Press drone footage over the weekend showed a yellow excavator digging into dirt and authorities in hazmat suits with shovels.

"We have obtained a massive amount of material," Tierney said at a news conference Tuesday outside the Massapequa Park house where Heuermann lived with his wife and two kids. "It's going to take quite some time."

Heuermann was arrested July 14 and charged in the deaths of Melissa Barthelemy, 24, Megan Waterman, 22, and Amber Costello, 27, who were sex workers before they were killed. They were found wrapped in burlap on Ocean Parkway in Gilgo Beach on Long Island in 2010. He's also a prime suspect in the death of a fourth woman, Maureen Brainard-Barnes, 25, but he has not been charged in that case. The women are commonly referred to as the "Gilgo four."

What weapons were found at the house?

Investigators found dozens of weapons in a "vault" in the basement of the house that was a large enough area for a person to enter, Tierney said.

There were a total of 279 weapons found. Tierney said they were all "what would commonly be referred to as a firearm" but some might not meet state or federal classifications to be considered a firearm.

Heuermann had 92 handgun permits, and there were "quite a few long guns as well," Tierney said.

What were investigators looking for?

Tierney said crews pored over a huge amount of items in a house that "could be categorized as cluttered." He said there were a lot of boxes and other things cluttering the house and the basement.

"We were looking for tangible items of evidence as well as trace evidence, including blood and DNA, hair fibers and the like," he said.

There were no large items of evidence recovered either in the house or the backyard, Tierney said. Crews excavated the yard after using technology to scan the ground and found a number of "disturbances." Tierney said those disturbances could have been anything under the ground, including a cistern or even a branch.

"There was nothing of note taken from the backyard as far as remains," he said.

He said the investigation into whether any of the women died on the property hasn't been conclusive either way.

The killings of the three women happened while the rest of Heuermann's family was out of town, and there isn't any indication his wife or children knew about the incidents, Tierney said Tuesday.

What comes next in the case?

Heuermann, who worked as a New York City architect, is due in court in on Aug. 1. He has denied the charges.

Tierney said the next stages in the case in court will include procedural issues and discussions of discovery.

TIMELINE:What led to arrest of suspect Rex Heuermann in Long Island?