Officials think a serial killer could be to blame in the death of a former Pinellas woman.
Published Jan. 28, 2011

Amber Lynn Costello was "a kind, loving, beautiful person" who turned to Christianity to recover from a rough past, her close friend said.

She came to Pinellas County four or five years ago and soon immersed herself in activities at local churches, said M'rissa Rosenthal, 34, a member of Lion of Judah Foursquare Church in Dunedin.

Now, police think the petite 27-year-old may have been the victim of a serial killer.

Last month, they found Costello's body on a desolate beachfront strip in Long Island, N.Y. The bodies of three other women were found in the same marshy area. Authorities think the women, all in their 20s, may have been slain by the same person. All were prostitutes who advertised online, officials said.

No one has been arrested, and authorities are not saying whether they have any suspects.

Police identified Costello earlier this week, saying she was last seen in North Babylon, N.Y., on Sept. 2.

Five feet tall and 100 pounds, Costello grew up in the Wilmington, N.C., area, according to Cherie Malpass, 55, whose husband is Costello's cousin. When Costello was a young teen, she often visited Malpass' house and hung out with her daughter.

"She was hyper, happy and energetic," Malpass said. "She never did cause trouble or anything like that."

She was a sweet girl, Malpass said. "She just got mixed up with the wrong people."

Malpass said she was aware that Costello was in the escort business when she lived in North Carolina. But several years back, around 2006, Costello was adamant that she was turning her life around.

She got a job as a server at a diner. She said she was "with the Lord," was going to church and was in the choir, Malpass said.

Rosenthal said a couple at a North Carolina church supported Costello.

"She had a hard life. They really helped her. And then she moved here," said Rosenthal, who met Costello around 2006 at a church retreat. Costello's sister lived in St. Petersburg at the time, Rosenthal said.

Costello, who also attended First Assembly of God in Clearwater, helped in the church nursery, Rosenthal said.

"She had a heart for children," she said.

Costello took great joy in helping her friends, too. She handled all of the arrangements when Rosenthal's beloved grandfather died.

"She was by my side when my grandfather died, and she took care of everything that needed to be done for me that I could not do for myself," said Rosenthal, who lives in Clearwater.

Costello lived in St. Petersburg, in the High Point area near Largo and in Clearwater, records show.

She married Donald Costello in December 2007. The couple divorced last March. He did not return several messages for comment this week.

Costello's address in High Point matches the address of the former president of Private Playmates Escort Referrals. That company was dissolved in 2008 because it didn't file an annual report, state records show.

Rosenthal said Costello didn't mention anything about the escort business.

But she thought Costello may have gotten on the wrong path because she had been "victimized."

"She was seeking healing for that," Rosenthal said. "A lot of women that end up doing that have been abused. But that was not the heart of who Amber was as a person."

Rosenthal said she last heard from Costello in the summer of 2009.

In December 2009, Costello was arrested on suspicion of shoplifting a few items, including toothpaste, from a Pinellas Park Publix supermarket, police records show. She told police she was an assistant at the Clearwater Library, but the city doesn't have any record of her employment. There's still an active warrant for her arrest because she failed to show up for court on the petty theft charge.

Police in New York found the first woman's body in mid December near a beachfront highway that leads to Jones Beach State Park. The other three women were found two days later during a followup investigation.

Last week, authorities identified one of the victims: Megan Waterman from Scarborough, Maine. Two others along with Costello were identified Monday as Maureen Brainard-Barnes of Norwich, Conn., and Melissa Barthelemy of Erie County, N.Y.

"What happened was an awful, horrific tragedy, and I am praying that it stops here and that whoever did this is caught," Rosenthal said.

A reward of up to $5,000 is being offered for information leading to an arrest in this case. Detectives are asking anyone with information to contact the homicide squad at (631) 852-6392 or Crime Stoppers at 1-800-220-8477.

Information from the Associated Press was used in this report. Lorri Helfand can be reached at or (727) 445-4155.