Suspected Gilgo Beach killer Rex Heuermann is “very comfortable” in jail and promised officers that he would be “extremely compliant” – but still has not received any visitors, the Suffolk County sheriff said.

Heuermann, 59, remains in custody at the Suffolk County Correctional Facility in Riverhead one week after he was arrested and hit with multiple murder charges in relation to the deaths of three women over a decade ago.

“He’s in the cell by himself, he’s receiving all the services that any other person who’s incarcerated will receive,” Suffolk County Sheriff Errol Toulon told WCBS 880 on Wednesday.

“It seems like he’s very comfortable in his cell and his surroundings. He’s indicated to my staff that he would not be any issue to us and would be extremely compliant, so we’ll see how that plays out in the days and weeks ahead,” he added.

As of Thursday, the architect is still in a single cell and remains on suicide watch, The Suffolk County Sheriff’s Office confirmed to The Post on Thursday.

Rex Heuermann was arrested last week.
Suffolk County

Toulon told WCBS suicide watch is “pretty standard for someone that comes in with a case of this type of notoriety.”

“Our mental health staff will reevaluate him to see if they actually do feel he has suicidal tendencies,” he explained.

Heuermann has also not received any visitors, the Sheriff’s Office told The Post.

The Suffolk County authorities are taking every precaution to ensure Heuermann’s safety, Toulon told Newsday this week.

He is being housed on a special unit that is only accessible to authorized personnel, spokesperson Vicky DiStefano told the outlet.

Suffolk County Correctional Facility.
The South Shore native is currently on a special unit of the Suffolk County Correctional Facility.
Getty Images

The Massapequa Park resident is monitored and videotaped 24 hours a day, and “all inmate movement stops” when he is moved from one place to another within the jail, Toulon explained.

Because of COVID-19 protocols, Heuermann is being quarantined for 10 days.

He has standard access to a television in the hallway, and is allowed out of his cell for showers and phone calls.

Heuermann’s wife, Asa Ellerup, 59, filed for divorce in Suffolk County Supreme Court on Wednesday, records showed.

Heuermann's family home in Massapequa Park.
Police have combed through Heuermann’s family home in Massapequa Park.
James Messerschmidt for NY Post

Heuermann pleaded not guilty last Friday to two counts each of first and second degree murder in connection with the deaths of  deaths of Melissa Barthelemy, 24, Amber Lynn Costello, 22, and Megan Waterman, 27.

The three women’s remains were discovered strangled and wrapped in burlap in the marshes along Ocean Parkway near Gilgo State Park in December 2010.

He is also the prime suspect in the death of Maureen Brainard-Barnes, 25, who was the first of the so-called “Gilgo Four” to disappear.

Rex Heuermann.
Heuermann has been linked to burner phones used to contact the Gilgo victims and their families.
Suffolk County

Despite the flood of tips and unnerving allegations about Heuermann’s past behavior, his defense attorney insists he is being railroaded for crimes he did not commit.

A crime laboratory officer moves a cat scratching post as law enforcement searches the home of Rex Heuermann.
Heuermann reportedly kept about 300 guns in his basement.

“He was articulate, he was intelligent, he was soft-spoken,” Michael Brown said of Heuermann, who was alternately described by a former work acquaintance as “a big talker.”

The 6’4” South Shore native was “traumatized” by his arrest, Brown added.

The investigation into Heuermann now spans several states, as police in South Carolina and Nevada are reportedly reexamining unsolved cases near his properties in both areas.