(NewsNation) — Rex Heuermann, the man already suspected in the deaths of four women found near Long Island’s Gilgo Beach, was charged in the murders of two more women Thursday during his latest court appearance.

According to a bail application released Thursday morning by Suffolk County District Attorney Ray Tierney, Heuermann faces additional second-degree murder charges for the deaths of Jessica Taylor and Sandra Costilla.

Taylor, 20, went missing in 2003 while working as an escort in New York City. Some of her remains were discovered in Manorville that year, and more were found by the side of Ocean Parkway. The body of 28-year-old Costilla was discovered in 1993.

Since 2010, police have been probing the deaths of at least 10 people, most of whom are sex workers, whose remains were discovered along an isolated highway not far from Gilgo Beach.Victims had gone missing over a span of at least 14 years. 

Heuermann, an architect who lived across a bay from where the bodies were found, was arrested last July in connection to the killings of Megan Waterman, Melissa Barthelemy, Amber Lynn Costello and Maureen Brainard-Barnes.

At Thursday’s hearing, Heuermann pleaded not guilty to killing Taylor and Costilla was ordered held without bail. Michael Brown, Heuermann’s attorney, told reporters after that Heuermann is “horrified by the new charges,” and “obviously in a bad place” regarding them.

Alleged ‘planning document’

Police have searched Heuermann’s home twice, and one piece of evidence they said they found in his basement was a Microsoft Word document named “HK2002-04.” Though it had been deleted, forensics experts were able to recover it. Included in the documents was a “checklist of supplies” including ropes, saws and surgical drapes.

“The task force believes that this is a planning document that was utilized by Heuermann to methodically blueprint and plan out his kills with excruciating detail,” Tierney said at a news conference Thursday. “His intent was specifically to locate these victims, to hunt them down and to bring them under his control and to kill them. His motivations, meticulous planning and clear intent is obvious.”

Included in the document are a series of checklists, including reminders to clean the bodies, destroy evidence, “get sleep before hunt” and to “have story set.” In another entry, called “things to remember,” it meantions “using heavier rope” and limiting noise.

Other evidence in latest victims’ case

More of what investigators found was detailed in the bail application, which also includes more information about the condition of the victims’ remains.

In 2003, a person walking their dog found Taylor’s remains and called 911, according to the document. She had been found decapitated, lying on her back, with her legs bent underneath her. Both of Taylor’s arms were severed from her body below her elbows and a tattoo on her torso had been “severely obliterated” by a sharp object, according to the court records.

Taylor’s skull, hands and forearm were later discovered along Ocean Parkway, just east of Gilgo Beach. The remains were on the same side of the road from where Brainard-Barnes, Barthelemy, Waterman and Costello’s had been found. 

A male human hair was recovered on Taylor, from a surgical drape that she had been underneath, according to police. It was sent to a mitochondrial testing laboratory, as well as a nuclear DNA testing lab, and test results showed that results were able to exclude most of the population except for Heuermann. 

Costilla’s remains were found in November 1993 by two people hunting in a wooded area of Southampton. She had been lying on her back, her arms outstretched over her head, with her uncovered legs spread apart. Costilla’s shirt was pulled over her torso and head, the bail application document said, and there were multiple sharp force injuries to her body. Hairs found on Costilla were also sent for testing and also pointed to Heuermann, the bail application said.

Taylor’s mother, cousin speak out

During the press conference, lawyer Gloria Allred, who is representing the family members of some victims, including Taylor, read a statement from her mom, Elizabeth Baczkiel.

“Jessica was my daughter. She was loving and compassionate and so funny,” Baczkiel wrote in the statement. “She loved to make people laugh. She could always make people laugh. She tried very hard in school.”

While Taylor never had kids, she loved working with them, Baczkiel wrote in the statement, and worked as an aide for an inner-city summer camp.

“She loves supporting kids and helping to take care of them,” Baczkiel said.

One of Taylor’s cousins, Jasmine Robinson, also at the news conference, said she looked up to her.

“When I think of her I see her smile first, big and bright lighting up her face, beaming through her beautiful eyes,” Robinson said. “She was a force, one of the strongest women that I know with a heart of gold. She was and still is loved immeasurably. When her life was stolen, a light went out. She is forever missed.”

The Associated Press contributed to this report.