CARROLL GARDENS, Brooklyn (PIX11) — The disappearance of a 12-year-old girl on her way to junior high school in 1991 is getting talked about again, along with two other cold case murders that year, after the arrest of an architect in the Gilgo Beach serial killer case.

In 1991, Gilgo suspect Rex Heuermann was a 27-year-old apprentice to an architect living on Carroll Street in Park Slope, a street that leads directly into the adjacent Carroll Gardens neighborhood.

On Oct. 10, 1991, 12-year-old Tiffany Dixon vanished after dropping off her younger cousin at an elementary school in Carroll Gardens. She never made it to her seventh-grade class several blocks away.

The online true crime site “Murder Incorporated” noted that Tiffany Dixon lived on Hart Street in Bushwick. Eight months after her disappearance, Rex Heuermann filed a request to do work on a property located at 689 Hart Street, up the block from where Dixon was living with her aunt and cousin.

Two weeks later, on Oct. 30, 1991, the body parts of a Park Slope woman, Sandra Acosta, were discovered at a weeded lot near the Gowanus section of Brooklyn. Her two hands, feet, arms and legs were found, along with her head. Her torso was never recovered.

PIX11 News covered the story at the time, and residents wondered if a serial killer was on the loose in Brooklyn.

Luz Carrion, the sister of victim Sandra Acosta, was distraught when speaking to PIX11 at her front door on Douglass Street.

“Somebody set out to do this,” Luz Carrion said in 1991, “not only to her but other people because there’s a lot of young girls missing, about three others. Same color hair, about the same height, weight, same area. The other girl is three blocks away from here, Tiffany.”

Luz Carrion referred to the missing Tiffany Dixon, who was never found.

Sandra Acosta was slim and petite, standing only about 4 feet eleven inches tall.

In the Gilgo Beach case, Rex Heuermann has been accused of targeting—and murdering—slim, petite women working as escorts.

The Suffolk County District Attorney, Raymond Tierney, released a 32-page court document on July 14 revealing Heuermann did extensive online searches for torture porn and child porn—looking up topics like 10-year-old school girl and age 12 child girl, among many others.

And there was another murder in 1991, in June of that year, with a Bushwick connection.

A young Korean immigrant, Su Ha Kim, who owned a store in Bushwick, was found naked in a dumpster, fatally stabbed in the Bedford-Stuyvesant section of Brooklyn. The killer had inflicted nine knife wounds.

The program “Unsolved Mysteries” has profiled the murder multiple times.

A security guard patrolling the Bedford-Stuyvesant property said he had come upon a white man with glasses near a dumpster at 3 a.m. on June 29, 1991. When the guard told the man he was illegally on the premises, the man offered the security guard $20 not to notify authorities. The guard said he noticed blood on the man’s shirt. When the man left, the security guard checked the dumpster and found Su Ha Kim’s body.

The young mother had two sons and was married for ten years to her husband. The couple had opened two stores, including one in Bushwick, Brooklyn.

The security guard gave police a license plate number that led them to a car at C.W. Post on Long Island.

It belonged to a female Asian exchange student at the college who had not driven the vehicle the night before.

The case remains unsolved.

But true crime researchers note that Rex Heuermann graduated from the New York Institute of Technology, a one-minute drive from the C.W. Post campus in the Old Brookville/Westbury area of Long Island.

A look at three cold cases that are getting some attention again, even though Rex Heuermann has not been formally tied to any of them. The Suffolk County District Attorney said he’s focusing on prosecuting Heuermann for the first murder victims discovered in Gilgo Beach in 2010.

Yet cold case detectives are already reviewing their old files to see if there could be any possible connection to the accused Gilgo killer.