New York (CNN) -- Suffolk County Police have upped the ante in their search for a killer or killers who apparently dumped their victims along a remote stretch of beach in Long Island, New York.
The reward for information leading to an arrest -- once topping out at $5,000 -- was raised five-fold, according to a police statement Thursday.
The $25,000 reward would be the largest offered in Suffolk County history, in an apparent bid to fill out a possible serial killer case that some fear has gone cold.
"We're hoping the increased reward money will encourage somebody to come forward by calling the police in respect to the families and to (the) victims," Lt. Robert Donohue said.
At least 10 sets of human remains have been found in Long Island's Nassau and Suffolk counties since December.
The woman who originally prompted the searches -- 23-year-old Shannan Gilbert -- remains missing, and police say they have sifted through more than 1,000 tips related to the case.
The New Jersey woman was last seen in May 2010 at a private party at a home in the Oak Beach community.
"I am hopeful that the increased reward will provide critical information to help bring those responsible to justice," Suffolk County Police Commissioner Richard Dormer said.
Like the four victims who were found in December and have since been identified, Gilbert advertised prostitution services on websites like Craigslist.