Rex Heuermann was a little-known Manhattan architect and married father of two one year ago today.

A few days later, he became known around the world as Long Island’s suspected Gilgo Beach serial killer.

Over the past 12 months, the murder charges against Heuermann doubled, searches of his property yielded massive amounts of evidence and prosecutors said he plotted his kills in a detailed manifesto.

News 12 broke the news that police had made a bombshell arrest in the Gilgo Beach murders investigation on July 14, 2023. At the time, Heuermann was charged with the murders of three victims: Melissa Barthelemy, Megan Waterman and Amber Costello.

In January, prosecutors charged Heuermann with the death of a fourth victim, Maureen Brainard-Barnes.

By June, Heuermann was accused of killing six women, including Sandra Costilla and Jessica Taylor. He currently is a suspect in the murder of Valerie Mack and allegedly began preying on victims at least three decades ago.

Investigators closely monitored Heuermann for more than a year before taking him into custody.

Since his arrest, investigators searched his two storage units, retrieved his car from South Carolina and scoured his Massapequa Park home - twice. Prosecutors have collected a mountain of evidence including thousands of terabytes’ worth of data from dozens of electronics.

“There is a significant pre-charge investigation that certainly is taking place in this case and, my expectation is, will take place before Mr. Tierney decides whether he wants to charge any additional offenses at this point,” said Marc Gann, a criminal defense attorney and former Nassau County prosecutor.

Prosecutors have built their case on circumstantial evidence, which includes cellphone data, DNA and Heuermann’s internet search history. Gann said circumstantial evidence could be more powerful than any potential eyewitness account.

“Those kinds of searches that he conducted purportedly, the kinds of materials that he held on to, could be very difficult for the defense to explain,” Gann said. “Eyewitnesses have their own problems in terms of recollection, in terms of bias, in terms of ability to detail what it is that they saw.”

As the prosecution moves forward building their case, Heuermann’s defense team might find what they’re looking for in the past. They are reviewing thousands of old leads on other suspects - names that police investigated years before Heuermann was on their radar.

“Certainly, if I'm the defense lawyer, one of the big things I'm going to try to focus on is the other suspects,” said Gann. “How they were ruled out, if they were. Why they were ruled out. Whether we can establish any connection to any one of these women.”

Gann estimates that the earliest start date for a trial would not be until next fall. Though there are standards and deadlines, the court can extend timelines to ensure both sides have ample time to review all the evidence in this high-profile case.