NEW YORK (PIX11) — A New York City man hired by Rex Heuermann’s firm, RH Consulting & Associates, for over three years told PIX11 News the arrest caught him by surprise. 

"Total shock! You know? At first, the shock of hearing of this, then obviously, the next thing comes to my mind. What happens to my job and my family?" said Damien Richards. 

In an exclusive phone interview with PIX11, one of Heuermann’s employees spoke about his boss's demeanor. 

“When he’s having a good day, he’s alright, but when not, he’s not the best person to be around,” Richards explained. “I've never witnessed him be violent - but he gets aggravated.”

Richards said he last spoke to Heurmann hours before his arrest in Midtown.

"I spoke to him twice...The last call was 1 p.m. [thursday] afternoon," recalled Richards. 

Suffolk County's Police Commissioner Rodney Harrison made the call to move in, concerned about possible Grand Jury leaks or even that the suspect could kill right under their noses.

"We took a look at where we were and said we have to move forward," said Harrison. 

"Because he did use phones and continue to contact sex workers, that was concerning to us," District Attorney Ray Tierney added.

For the fourth straight day, the meticulous process of confiscating and cataloging evidence from the suspected serial killer’s home on First Avenue continued in Massapequa Park.

And a search warrant was executed there as well, two and a half miles away at Heuermann’s self-storage unit in Amityville. 

"Anything he had a connection to, his residence, work, we have to get search warrants to see if there body parts or trophies of the victims," Harrison explained.

Investigators hope that will shed light on whether the 59-year-old had any additional alleged victims other than the Gilgo Four he’s been tied to in the indictment. 

"The amount of evidence that we're getting both digital forensic is so massive," Tierney said. 

New York State Police lauded one of its own Monday for cracking the case wide open. Maj. Stephen Udice of Troop L said it happened a month after their investigator was assigned the case last February.

Sources said the trooper used the killer's and victim’s cell phone data and matched his potential vehicle to identify Heuermann by name.

"And confirmed Rex Heuermann was responsible for, at minimum, the deaths of three women," said Udice. 

Heuermann has denied any involvement in the case and has been placed on suicide watch at the Suffolk County Jail.