NEW YORK -- As investigators dig into the "double life" of suspect Rex A. Heuermann, the Manhattan architect charged in the murders of three women in Long Island, they're also checking to see if they can tie him to unsolved murders or missing persons cases throughout New York state, an NYPD official told ABC News.
Police throughout New York are interested in whether they might be able to tie Heuermann to victims beyond Gilgo Beach. Detectives are now checking to see if his DNA or behavior fit unsolved murders and missing persons cases in New York City, an NYPD official told ABC News.
Additionally, Heuermann's DNA has been entered into a statewide database, available to all law enforcement agencies in New York.
Heuermann, 59, has been charged with the murders of Melissa Barthelemy, Megan Waterman and Amber Costello, whose bodies were found covered in burlap along Ocean Parkway on Long Island's South Shore in December 2010. He was also named the "prime suspect" in the death of Maureen Brainard-Barnes, a fourth woman discovered in the same spot, police said.
Heuermann appears to fit into a profile of serial killers who've led double lives, a former FBI agent said.
Some suspects in serial crimes appear to lead normal lives at work and home, which they can separate from their misdeeds, Brad Garrett, a former FBI profiler, told George Stephanopoulos on Monday's "Good Morning America."
"Serial offenders lead parallel lives -- in other words, George, they can do horrendous things, kill people, torture people, whatever it might be," Garrett said. "They can go home, they can feed their kids, they can kiss their wives goodbye ... and their life goes on."
The architect commuted into New York City from his home in Massapequa Park, where he lived with his wife, according to court documents. He's a father of two, the documents said.
But, at the same time, he allegedly signed up for online accounts using fictitious names to search for sex workers for "dates" or "hookups," according to court documents. And he also had permits for 92 firearms, prosecutors said.
"That's why the term 'hide in plain sight' is very relevant to serial offenders," Garrett said.
Heuermann's defense attorney, Michael Brown, said in a statement Monday: "There is nothing about Mr. Heuermann that would suggest that he is involved in these incidents. And while the government has decided to focus on him despite more significant and stronger leads, we are looking forward to defending him in a court of law before a fair and impartial jury of his peers."
Police remained on Monday at his Massapequa Park home searching for clues.
They also searched a storage unit bin in nearby Amityville as they try to solidify the case involving the three first-degree murder charges and see if they can tie him to the six other Gilgo victims, all found along the same stretch of beach in late 2010 and early 2011.
"I wouldn't be surprised" if they found additional cases to tie Heuermann to, Garrett said, but he warned that the suspect may have "changed" his pattern after bodies were found on Gilgo Beach in 2010.
ABC News' Ivan Pereira contributed to this report.