Two women held in Suffolk County jail say they had encounters with accused Gilgo Beach serial killer Rex Heuermann, describing the meetings with him as "violent" and "aggressive," sheriff's department spokesperson Vicki DiStefano said Thursday.

The alleged encounters with the two female sex workers are believed to have happened more than a decade ago, said DiStefano, noting the women expressed concern for their safety during the time they say they were with Heuermann.

The information was uncovered as part of ongoing interviews by the Suffolk County Sheriff's Department human trafficking unit, which was created to help those incarcerated have access to services and support they need to recover.

Since Heuermann's July 13 arrest, the unit has been interviewing sex workers, as well as showing a picture of Heuermann to women, to see if they recall any interactions with him.

So far, five women have given information considered helpful to authorities, DiStefano said.

The unit, which started in 2018, is also working with the Nassau County jail and Rikers Island in New York CIty to see if other connections with Heuermann exist.

CNN has reached out to Heuermann's attorney for comment.

Heuermann was arrested July 13 in New York City, where he worked as an architectural consultant, and charged with murder in the deaths of three of the "Gilgo Four" -- women whose remains were found in 2010 along a short stretch of Ocean Parkway in Gilgo Beach.

He has pleaded not guilty in the killings of Melissa Barthelemy, Megan Waterman and Amber Lynn Costello.

The 59-year-old architect is also the prime suspect in the disappearance and killing of the fourth woman, Maureen Brainard-Barnes, but he has not been charged in that case.

Heuermann was first identified as a potential suspect in early 2022, shortly after a multi-agency task force was formed to examine cold cases involving nearly a dozen sets of human remains found along Long Island's South Shore between 2010 and 2011, including the Gilgo Four.