Investigation timeline of Gilgo Beach murders

Police have called the Gilgo Beach murders "one of the most consequential homicide investigations" in Long Island's history.

The search for missing sex worker Shannan Gilbert led to the grisly discovery of 10 other bodies on a stretch of beach along the island's South Shore.

Now, nearly 13 years after the first victim was discovered, a suspect has been arrested in connection with the case.

New York City architect Rex Heuermann has been charged with the murders of Melissa Barthelemy, Megan Waterman and Amber Costello, whose bodies were found covered in burlap in December 2010, according to court records.

Heuermann, 59, a married father of two, is also the "prime suspect" in the death of a fourth victim, Maureen Brainard-Barnes, who was also found that month, according to the court document. He has not been charged with her murder.

The four victims have become known as the "Gilgo Four"; the Craigslist escorts were found along the beach about 500 feet from each other, and all died by homicidal violence, according to officials.

Here's a timeline of the investigation.

July 9, 2007

Brainard-Barnes, 25, is last seen alive in New York City, according to prosecutors.

July 10, 2009

Barthelemy, 24, is last seen alive in New York City, according to prosecutors.

May 1, 2010

Gilbert, 23, goes missing after fleeing from a client's home in Oak Beach, near Gilgo Beach, according to police. Her disappearance prompts several searches in the area.

June 6, 2010

Waterman, 22, is last seen alive at the Holiday Inn in Hauppauge, New York, according to prosecutors.

Sept. 2, 2010

Costello, 27, is last seen alive at her home in West Babylon, New York, according to prosecutors.

Dec. 11, 2010

An officer conducting a search for Gilbert with his police K9 along Ocean Parkway in Gilgo Beach -- near her last known location -- discovers a set of human remains that are later identified to be those of Barthelemy, police said.

Dec. 13, 2010

During a search of the area, police find the remains of Brainard-Barnes, Waterman and Costello within a quarter mile of where Barthelemy's remains were recovered, police said.

March 29, 2011

Amid the continued search for Gilbert, police find partial skeletal remains several miles east of where the Gilgo Beach Four were found belonging to Jessica Taylor, a 20-year-old sex worker. Other remains from Taylor were previously discovered in Manorville, in eastern Long Island, in July 2003.

April 4, 2011

Police find three sets of remains along Ocean Parkway while searching for Gilbert.

The remains of Valerie Mack, a 24-year-old escort who disappeared while living in Philadelphia, are found about a mile and a half east of Taylor's remains and a little over 2 miles east of the Gilgo Four. Mack's partial remains were previously discovered in Manorville in November 2000, and police have suggested there may be a connection to Taylor's remains.

The remains of an unidentified female toddler are also located in the same area.

The remains of an unidentified man are also discovered closer to the remains of the Gilgo Four. Authorities said the person was about 17 to 23 years old, Asian, and had died five to 10 years before being discovered.

April 11, 2011

Two sets of remains are located off of Ocean Parkway in Nassau County, seven miles west of Gilgo Beach.

One set of remains is determined to be the mother of the female toddler discovered on April 4, 2011. The mother’s partial remains were first discovered in 1997 in Hempstead Lake State Park.

The second set, known as Jane Doe Seven, is confirmed to belong to an unidentified victim whose remains were located on Fire Island in 1996.

Dec. 13, 2011

Gilbert's remains are found in marshland near Oak Beach. Her death is later ruled as an accidental drowning, though her family maintains they believe she was murdered.

January 2022

The Suffolk County District Attorney's Office creates a task force to conduct a comprehensive review of evidence in the investigation.

March 14, 2022

Heuermann first comes up as a suspect in the investigation, according to Suffolk County District Attorney Ray Tierney. Heuermann was tracked through his car, a Chevrolet Avalanche, according to court documents. A witness to Costello's disappearance reported seeing a Chevrolet Avalanche at Costello's home, court records stated.

July 13, 2023

Heuermann is arrested in Manhattan at his midtown office. Investigators matched DNA from hair recovered from the burlap used to wrap Waterman's body to leftover pizza crust Heuermann threw into a Manhattan garbage can in January 2023, according to court documents.

Detectives also tracked Heuermann through cellphone records, according to court records. Tierney said cellphone mapping led investigators to zero in on areas in midtown Manhattan and Massapequa Park, where Heuermann lives.

July 14, 2023

Defense attorney Michael Brown enters a not guilty plea on Heuermann's behalf at his arraignment for three counts of first-degree murder and three counts of second-degree murder. Heuermann was ordered held on no bail.

Aug. 4, 2023

Authorities announce they have identified Jane Doe No. 7, whose remains were first located on Fire Island in 1996, as 34-year-old Karen Vergata. More of her remains were found on April 11, 2011, on Long Island's Tobay Beach.

There are no charges at this time, Suffolk County District Attorney Raymond Tierney says.

ABC News' Aaron Katersky, Jon Haworth, Emily Shapiro, Josh Margolin, Mark Osborne and Mark Crudele contributed to this report.