He came face to face with an alleged serial killer. 12 years later, his tip helped crack the case

More crucially, Schaller told them about the man's truck.

The man they were looking for was a towering, Frankenstein-like figure with an "empty gaze" who drove a first-generation Chevrolet Avalanche, Schaller recalled telling investigators. The man's size stuck out, as did his unusual pickup truck, which he'd used to flee the house Schaller shared with Amber Costello.

On that night, Schaller said he came home to find the stranger threatening Costello, an occasional sex worker, who locked herself in the bathroom. The two men came to blows, and the hulking intruder eventually left in the truck.

Prosecutors say Costello was last seen alive Sept. 2, 2010, as she left her home to meet that same client. A witness saw a dark-colored truck drive by the house again shortly after she left.

"When they told me she was dead, he was the first person who jumped in my head," Schaller said. "I've been picturing his face for 13 years."

On July 14, police arrested Rex Heuermann on charges of killing Costello and two other women: Melissa Barthelemy and Megan Waterman. He is the prime suspect in the death of a fourth woman, Maureen Brainard-Barnes.

Heuermann, an architect who worked in Manhattan, pleaded not guilty to the charges.

The arrest marked a stunning breakthrough in the hunt for a serial killer who eluded investigators and whose crimes gripped Long Islanders since the bodies of four women — all of them sex workers — were found wrapped in burlap near Gilgo Beach.

Within months, the remains of six other bodies, including a toddler, were discovered elsewhere along the same beach highway. Heuermann has not been accused in those cases; police said the deaths may be the work of multiple killers.

The arrest brought a measure of relief to families of the victims at a moment when the trail appeared to have gone cold. However, as new details emerge about how police finally caught the alleged killer, they've also raised questions about whether investigators adequately pursued a key lead — Schaller's description of the stranger and his truck — that could have helped solve the case sooner.

"This was crucial information, and I don't know why they didn't share it," said Rob Trotta, a county legislator who worked as a Suffolk County Police detective until 2013. "They made some serious blunders here."

Suffolk County District Attorney Ray Tierney, who inherited the investigation when he took office in 2022, said the key to unraveling the case was the description of the truck, discovered by a state investigator after the launch of a new task force formed to take a fresh look at the evidence.

When they ran it through a vehicle records database, one of the results turned up a hit: A man who owned a Chevy Avalanche lived in a neighborhood that investigators were zeroing in on as the suspect's likely location because of a sophisticated analysis of cellphone location data and call records. Heuermann fit the physical description provided by Schaller, too: He was 6 feet, 4 inches tall and weighed 240 pounds.

Those involved in the case pointed to fierce divisions between the various law enforcement agencies — as well as overlapping scandals that engulfed Suffolk County — as a potential explanation for a key clue slipping through the cracks.

Tierney said he did not know why police had not run a search earlier but suggested the piece of information may have been "lost within a sea of other tips and information."

He stressed there were other elements that ultimately helped investigators arrest Heuermann, including new technology that helped match samples of DNA to the suspect.

"What solved this case was a lot of dedicated investigators, analysts and attorneys from a bunch of agencies getting together and collaborating," he said.

For Schaller, any feelings of relief over the arrest were soon eclipsed by anger and confusion.

Speaking out for the first time since the arrest, he said he met with homicide detectives on multiple occasions during the initial years of the investigation.

During one of their final meetings, roughly two years after the women went missing, he said he picked the truck's model out of a line-up of photographs provided by the detectives.

"I gave them the exact description of the truck and the dude," he said. "I mean come on, why didn't they use that?"

The question vexed some law enforcement officials as well.

Two high-ranking officials who worked closely on the case and attended briefings between 2011 and 2013 said they never heard anything about a witness statement describing the suspect and his vehicle. They spoke on condition of anonymity.

According to a vehicle history report, Heuermann bought the pickup — a dark green, first-generation edition — at a Chevrolet dealer on Long Island in 2002 and transferred ownership to his brother, Craig, in South Carolina in 2012.

Authorities seized the vehicle this month. In a search warrant, they said they were looking for other clues in the vehicle or at property the brothers owned in Chester County, South Carolina, and what they described as possible "trophies" — items that may have belonged to the victims, such as clothing, jewelry or photos.