- Search for Shannan Gilbert in 2010 led to discovery of 10 bodies on Long Island
- A cell phone was also found alongside a pair of jeans and shoes, police added
- "It is our belief her body or parts of her remains are in that area," police commissioner says
- Authorities are searching for a possible serial killer
The pocketbook of a New Jersey woman whose disappearance in 2010 led authorities to the discovery of 10 sets of human remains across two Long Island, New York, counties has been found, police said Wednesday.
A cell phone that authorities believe may also belong to Shannan Gilbert -- whose disappearance triggered a search that has become a hunt for a possible serial killer -- was also found on Long Island's Oak Beach, alongside a pair of jeans and shoes, according to Suffolk County Police Commissioner Richard Dormer.
"We're going to do everything we can to find her," he told reporters. "It is our belief her body or parts of her remains are in (an area of Oak Beach), and we will continue (to) search tonight and into tomorrow."
After Gilbert vanished in May 2010, the search for her led police seven months later to four bodies found along a quarter-mile stretch of Oak Beach. Additional remains were uncovered in subsequent months in neighboring Gilgo Beach and along beachfront property in Nassau County, about 40 miles east of New York City.
Like the four victims found last December, Gilbert had advertised prostitution services on websites such as Craigslist.
Gilbert's sisters have said the missing woman was an escort who was visiting a client. They said she ran from the man's house and called 911, saying someone was trying to hurt her.
A man who lives a few miles from where the first set of remains were found last December told CNN that a young woman who "looked like she was partying all night" came to his door at about 5 a.m. on May 1, 2010.
"She was screaming 'Help me, help me!' and said somebody was chasing her," said resident Gustav Coletti.
Wednesday's find comes after renewed search efforts by federal and state authorities in Oak Beach -- the area where Gilbert was last believed to be, at a so-called private party.
"This may be just a young lady (who) ran into the brush in hysterical state, fell down and expired for some reason," added Dormer.
The police commissioner announced earlier this week that the investigation likely revolves around a possible serial killer -- a departure from his prior statements, in which Dormer said the bodies could be the work of multiple killers.
It is not clear what prompted the change in focus toward one killer.
"What's common here is the dumping ground," he said.
Authorities have sifted through more than 1,000 tips related to the case, with police upping the ante in their search for a culprit.
The reward for information leading to an arrest -- once topping out at $5,000 -- was raised five-fold, making it the largest offered in Suffolk County history.