Gilgo Beach serial killer suspect Rex Heuermann is isolated in

Gilgo Beach serial killer suspect Rex Heuermann is isolated in prison “lonely and depressed” – as he appears in court again WITHOUT his blockbuster docuseries wife

The suspected Gilgo Beach serial killer appeared in court just weeks after pleading not guilty to killing a fourth woman.

Rex Heuermann, 60, was taken to a quiet Suffolk County courthouse in Riverhead, Long Island, New York, on Tuesday morning.

He appeared before Judge Timothy Mazzei in a black suit and white shirt to be updated on the status of his case.

His lawyer told that the accused killer was still being held in isolation in prison and was “lonely and depressed.”

It was the first time the architect had appeared in court since January 16, when he pleaded not guilty to killing sex worker Maureen Brainard-Barnes, 25, in 2007.

Rex Heuermann, 60, was taken to a quiet Suffolk County courthouse in Riverhead, Long Island, Tuesday morning

Rex Heuermann, 60, was taken to a quiet Suffolk County courthouse in Riverhead, Long Island, Tuesday morning

He appeared before Judge Timothy Mazzei in a black suit and white shirt to be updated on the status of his case

He appeared before Judge Timothy Mazzei in a black suit and white shirt to be updated on the status of his case

Heuermann's most recent court appearance, unlike his last, took place without his wife, 59-year-old Asa Ellerup.

In the past, she has attended her ex's court hearings along with a documentary camera crew to monitor developments in the case and has visited him in prison three times in the last six months.

This came after she filed for divorce to “protect” herself from future lawsuits, six days after her husband of more than 20 years was chained in his Manhattan office for the murders of three other women .

She was last seen outside the couple's home in Massapequa, a day after Heuermann denied killing another person before running errands with one of their two children.

She has reportedly signed a seven-figure deal with NBC Universal, Texas Crew Productions and G-Unit for a documentary about the case, which addresses allegations that her ex killed three sex workers on a stretch of Suffolk County beach in 2010 .

Last week he was hit with a fourth murder twist in a case involving the same stretch of beach where the body of Maureen Brainard-Barnes was found in 2010, near those of the other victims after she disappeared three years earlier.

It is believed that it was Heuermann's first of the four murders. This was followed in 2009 by the murder of Melissa Barthelemy, a 24-year-old sex worker, and the murders of prostitutes Megan Waterman, 22, and Amber Lynn Costello, 27.

All had advertised their services on Craigslist and Backpage, and all were found tied up in burlap sacks within a few miles of each other. Heuermann pleaded not guilty to murdering all four.

One of the most important events of Tuesday's hearing - apart from the conspicuous absence of Ellerup and the couple's 26-year-old daughter - was the handover to the defense of a trove of documents compiled by the prosecution.  Suffolk County District Attorney Ray Tierney is seen here

One of the most important events of Tuesday's hearing – apart from the conspicuous absence of Ellerup and the couple's 26-year-old daughter – was the handover to the defense of a trove of documents compiled by the prosecution. Suffolk County District Attorney Ray Tierney is seen here

An update was also offered on the suspect's incarceration at the Suffolk County Correctional Facility, where local suspect Sheriff Errol Toulon previously said Heuemann was

An update was also offered on the suspect's incarceration at the Suffolk County Correctional Facility, where local suspect Sheriff Errol Toulon previously said Heuemann was “extremely compliant” while awaiting trial

Heuermann's latest court appearance, unlike his last, came without his wife, 59-year-old Asa Ellerup, who was seen here running errands last month after her husband pleaded not guilty to killing a fourth woman

Heuermann's latest court appearance, unlike his last, came without his wife, 59-year-old Asa Ellerup, who was seen here running errands last month after her husband pleaded not guilty to killing a fourth woman

THE GILGO FOUR: Heuermann has now been charged with the murder of four women: Melissa Barthelemy, Amber Costello, Megan Waterman and most recently Maureen Brainard-Barnes

THE GILGO FOUR: Heuermann has now been charged with the murder of four women: Melissa Barthelemy, Amber Costello, Megan Waterman and most recently Maureen Brainard-Barnes

One of the key events of Tuesday's hearing – aside from the conspicuous absence of Ellerup and the couple's 26-year-old daughter Victoria – was the handover of a potentially incriminating trove of documents to the defense.

An update was also offered on the suspect's incarceration at the Suffolk County Correctional Facility, where his attorney said he was suffering from loneliness and the effects of nearly seven months of isolation.

Earlier, Sheriff Errol Toulon said Heuermann had been “extremely compliant” while awaiting trial.

In addition, a trial date has finally been set for the case that continues to fascinate the country.

However, film crews from Netflix – which is also working on a true-crime series about Gilgo Beach – were present for the proceedings, which began with the court-ordered seizure of 7 terabytes of data that investigators took from Rex's home office.

Michael Brown, Heuermann's attorney, is seen arriving at the Suffolk County Courthouse Tuesday morning

Michael Brown, Heuermann's attorney, is seen arriving at the Suffolk County Courthouse Tuesday morning

He and his colleague Danielle Coysh gave a press conference after the hearing, where the trial date was set for April 17

He and his colleague Danielle Coysh gave a press conference after the hearing, where the trial date was set for April 17

In the speech, the lawyer gave an insight into his client's everyday life in prison, where he has been held in isolation for six months

In the speech, the lawyer gave an insight into his client's everyday life in prison, where he has been held in isolation for six months

He said Heuermann sought counseling for the first time before comparing his client's isolation to being alone on a desert island

He said Heuermann sought counseling for the first time before comparing his client's isolation to being alone on a desert island

The defense, led by attorney Michael Brown, was also turned over an additional 2,500 pages of laboratory and underlying laboratory reports, as well as three additional terabytes of data downloaded from Heuermann's other electronic devices.

The bulk of investigators' case files revolve around Costello – a Suffolk County sex worker who sold her body to support her and her roommates' heroin addiction.

That file contained about 6,000 pages, said prosecutors, who opposed the release of the documents.

The dump was taken last year during police's clandestine surveillance of Heuermann and also contained DNA that is believed to be a key factor in the case, as the samples found on the bodies of the women bound with belts or red tape matched the samples from the case matched discarded food in Heuermann's Manhattan office.