Recently unveiled information sheds light on the first night behind bars for the suspect in the Gilgo Beach serial killings, offering a glimpse into his unsettling response to the grave accusations.

Rex Heuermann, apprehended by nearly a dozen undercover officers outside his Midtown Manhattan workplace on July 13, 2023, seemed caught off guard by the arrest.

The 62-year-old architect, a husband and father of two from Massapequa, Long Island, questioned, “What is this about?”

Heuermann further inquired, “What did I do?” and insisted to the officers that it was “a mistake.”

However, according to newly released police documents, Heuermann’s demeanor shifted during the hour-and-a-half journey with detectives from Midtown Manhattan to the Suffolk County Police Headquarters, where he adopted a surprisingly calm attitude.

The night’s events seemed to do little to dampen his appetite, as he spent his initial night in detention consuming French fries, onion rings, peanut butter crackers, and sipping on a Coca-Cola.

He then managed to sleep for more than five hours on a chair as he awaited arraignment.

Those details were revealed in a 178-page motion filed by his defense attorney, Michael Brown, ahead of a scheduled court hearing Tuesday. 

Alleged Gilgo killer Rex Heuermann appears in front of Judge Timothy Mazzei alongside his attorney Michael Brown at Suffolk County Court in Riverhead on Tuesday

His lead defense attorney, Michael Brown, had asked the judge to suppress certain evidence from the jury, including statements Heuermann made to detectives and court officers during his arraignment — remarks that prosecutors say reflect an unusual calmness in the hours after his arrest.

The records show that, after munching on junk food, Heuermann joked that he ‘won’t be needing that’, referencing his $6,000 watch as he was escorted to his arraignment by a court officer. 

Heuermann is charged with the murders of seven women over a two-decade reign of horror running from 1993 to 2011.

All the victims were working as sex workers when they vanished.

Their bodies were dumped along Ocean Parkway near Gilgo Beach and other remote spots on Long Island.

Some of the victims had been bound, while others had been dismembered and their remains discarded across multiple locations.

The Gilgo Beach serial killer case went unsolved for more than a decade – hampered by a corrupt police chief, James Burke, who was ultimately jailed for beating a man who stole porn from his police cruiser.

In July 2023 – following the launch of a new task force – Heuermann was dramatically arrested as he left his office in midtown Manhattan.

In the court documents, a prison log revealed that Heuermann was dressed in tan khakis, a short grey collared shirt, and dark shoes, his 6 ft. 4 inch frame, 280-pound frame towered over the police.

At Suffolk County Police Headquarters, police photographed and fingerprinted him, and during a search, they found $135 in cash.

One of the first meals he was given included French fries, onion rings, peanut butter crackers, and Coca-Cola. 

Though he had told officers he was a diabetic, he declined his medication.

At 4.20am, Heuermann was transferred to the Seventh Precinct, where he fell asleep in a chair for more than five hours. Hours later, he would be arraigned.

Heuermann was seen holding in a laugh as he stands next to lead attorney Michael Brown

Heuermann is charged with the deaths of Megan Waterman, Amber Costello, Melissa Barthelemy, Maureen Brainard Barnes, Sandra Costilla, Jessica Taylor, and Valerie Mack

Heuermann remains in custody at the Riverhead Correctional Facility in Suffolk County.

The new defense filing urges prosecutors to turn over records regarding two men the defense may seek to introduce as alternate suspects.

Heuermann’s ex-wife, Asa Ellerup, who has attended several hearings, did not appear in court on Tuesday, nor were any other family members present.

After more than two years since Heuermann’s arrest, Judge Mazzie is ready for the next step and announced that ‘the trial will begin after Labor Day, come hell or high water.’