The discovery that a serial killer used the woods behind a shopping center as a dumping ground for at least seven victims has sent a chill through nearby residents, despite assurances from police that the person responsible is no longer a threat to the public.

The victims — four discovered last month, in addition to three partial skeletons found in 2007 — were believed to have been killed a decade or more ago. They were buried in a 15-acre patch of land ringed by stores, other commercial buildings and a quiet neighborhood of green lawns and ranch-style homes.

"It's definitely eerie. You stare at the woods and dead bodies are back there," said Colin Meyer, manager of a nearby muffler and brake shop in this working-class Hartford suburb of 73,000 people. "It just makes you wonder though how many more could be back there. All there is is questions and no answers yet."

Police announced on Monday that number of dead had climbed to seven and that they were victims of the same person. But investigators have not said how they arrived at that conclusion, and they did not explain why the killer was no longer a threat — whether, for example, the suspect is already behind bars.

Joe Greca, a 64-year-old business owner who has lived in the neighborhood since 1974, said he was shocked by the latest findings and has begun closing the drapes on his windows at night.

"It worries me because I face the woods, and I never know who's going to be coming near my backyard," Greca said.

Authorities have not disclosed how the victims were killed. The four who have been identified so far disappeared in 2003, and police said the others appeared to have been left behind a decade ago or more.

"He must have used that for a dumping ground," said 52-year-old neighborhood resident Carmen Messina, who recalled playing in the same patch of woods with her friends as a child.

A hunter came upon the remains of the first three victims — Diane Cusack, Joyvaline Martinez and Mary Jane Menard. Police said all three women had drug or alcohol problems and were known to frequent the same downtown New Britain neighborhood.

Investigators returned annually to the site, and this spring a cadaver-sniffing dog on loan from the FBI helped locate the additional victims. One was identified as Melanie Ruth Camilini, a mother of two from Seymour.

No charges have been brought against the suspect, whose name was not released by police.

"We can only do that lawfully if we believe a suspect poses an imminent threat to the community," New Britain Police Chief James Wardwell said.