HUDSON COUNTY, N.J. (WPIX) — Meresa Hammonds’ son was a toddler when his mother disappeared from his life nearly 30 years ago, and he tried to hold out hope she would find him one day.

“It was hard growing up, thinking she was out there and not looking for me,” Jason Di Trapani told NewsNation affiliate WPIX.

What Di Trapani didn’t realize was that his mother was fatally beaten and dismembered on June 27, 1992, her remains thrown into a Yonkers dumpster behind a pizza restaurant. She was one of five victims of serial killer Robert Shulman, a Long Island postal worker who used to pick up women in Queens.

“He thought, you know, that she didn’t care for him, she didn’t love him, and that’s why she didn’t look for him or anything,” Detective John Geiss of the Yonkers Police Cold Case Squad said of the woman’s son, who’s now 35.

In mid-November, Detective Geiss met Di Trapani and told him that’s not the way it was.

“It took a long, long time to identify her,” Detective Geiss said.

Until early November, Meresa Hammonds was only known in police circles as Yonkers Jane Doe, the murder victim found in a dumpster behind the I Love New York pizza restaurant on Midland Avenue. Four years after Yonkers Jane Doe was thrown in the trash, some sex workers who survived an encounter with Robert Shulman tipped off police that something was shady about him. One of them remembered the Hicksville address where he rented a room. Several of them talked about his blue Cadillac.

When Shulman was arrested in April 1996, he confessed to the crimes and was sentenced to life in prison. He died 10 years later, in 2006.

And the identity of Yonkers Jane Doe remained a mystery.

In 2014, Detective Geiss decided he wanted to devote every resource he could to finding Jane Doe’s identity.

“Going through the autopsy reports, I knew she had two children,” Geiss said, “because she had caesarean scars. And I wanted to identify her.”

Geiss asked forensic genealogist and artist Carl Koppelman to do a rendering of what Yonkers Jane Doe  may have looked like when she was alive. He worked with her autopsy pictures to produce an image.

As it turned out, Koppelman “was right on the money,” Detective Geiss said.

In recent years, Geiss took note of genetic genealogy and its successful use in multiple, unsolved cases. This technique involves putting DNA in public websites to see if there’s a link with unknown relatives.

Dr. Colleen Fitzpatrick, a genealogist who’s president of Identifinders International and the co-founder of Doe DNA Project, started working with genetic genealogy in 2011, trying to help in the cold case murder investigation of Seattle teen Sarah Yarborough.

“We had the genealogy of the killer going back to the 1600s, but we didn’t know who he was,” Fitzpatrick said from her California office.

She said they solved it in 2019, however.

“The technology has advanced, the databases have gotten bigger,” she said.

Genetic genealogy was also famously used in the Golden State Killer case, resulting in the 2018 arrest of 72-year-old Joseph DeAngelo, a former cop who later confessed to 13 murders and 13 rapes. It’s believed he committed many more crimes.

“The Golden State Killer case opened up the revolution,” Dr. Fitzpatrick said.

She talked about the distrust of genetic genealogy as a law enforcement tool in its early days.

“I got hate mail, I was ostracized,” Fitzpatrick said.  “Now, we’ve gone from that alarm to more of an educated discussion.”

Fitzpatrick’s Identifinders International is now doing work in more than 50 countries globally.

Back in Yonkers, Detective Geiss said an FBI team put his Jane Doe’s DNA into genealogy databases and got results in three weeks.

Those results led him to Meresa Hammonds’ identity and a trip to Michigan, where he met the victim’s brother and some of her sisters.

He showed the autopsy photo to Hammonds’ brother and a picture of a butterfly tattoo that was on her back.

“He said, ‘That’s my sister! That’s her,” Detective Geiss recalled.

The detective’s last step was finding one of the victim’s sons in the New York area.

He talked to Jason Di Trapani and told him what had happened to his  mother in 1992.

“He was glad to learn about his  mom,” Detective Geiss said.

A DNA test confirmed Di Trapani was Meresa Hammonds’ biological son.

Now, he’s even met his mother’s large family during Thanksgiving gatherings.

“He does have family, her family, that want to be part of his life,” Geiss said.  “Something good came out of something bad.”

Jason Di Trapani has one last task he’d like to perform in his mother’s behalf — he wants to get her a headstone, with her name, so she’s no longer buried as Jane Doe in a Staten Island cemetery.

He’s appealing for donations with a GoFundMe page called “Yonkers Jane Doe 92.”