New York (CNN) -- Police say the search for a missing woman, which led investigators to the closely grouped remains of eight bodies in Long Island, New York, will expand Monday.
Investigators -- now embroiled in a manhunt for a potential serial killer -- are expected to spread out along the Nassau County line, working westward from Jones Beach in their search for Shannan Gilbert, who has been missing since May.
"We will be looking for human remains and any possible evidence," said Nassau Police spokesman Kevin Smith.
On Thursday, investigators said they were nearly finished with at least one part of the search effort in the Oak Beach area, where four female bodies were found stuffed in bushes along a quarter mile strip of beachfront property in December.
"Our search for (Gilbert) will continue, even though this component of the search is nearly over," Suffolk County Police Commissioner Richard Dormer told reporters.
K-9 units and dive teams had been added to the search operation in an effort to locate the missing woman, who was last seen alive in the neighboring Gilgo Beach area.
Police say the remains of three more bodies found earlier this week were uncovered within a few miles of each other, fueling speculation that they could be the work of a serial killer.
A woman's body was also found March 29 off Ocean Parkway, west of Cedar Beach.
The case has drawn international attention as state and federal investigators pieced together evidence alongside local authorities.
Gilbert's sisters said Shannan was an escort who was visiting a client. They said she ran from the man's house and called 911, claiming that someone was trying to hurt her.
Several neighbors also called 911, witnesses say.
Police came more than 30 minutes later, but by then Gilbert was gone and has never been heard from again.
"You want to believe everything was okay with her," Sherre Gilbert said. "But at the same time, so much time has passed it's impossible to really think that she is still alive."
Police say the hunt for a potential serial killer continues, as does the search for Gilbert.
She, like the women whose bodies have been identified, advertised for prostitution services on internet sites such as Craigslist, police said.
Sherre Gilbert said even if her sister isn't ever found, the search has led to one positive outcome: the discovery of eight other women.
Police have not yet confirmed the identities of the remaining four bodies.
CNN's Kaj Larsen, Rupa Mikkilineni and Jen Christensen contributed to this report