Two more sets of bones were discovered on Monday, bringing to 10 the total number [GALLO/GETTY]

Police searching for more victims of a suspected serial killer on New York's Long Island have expanded their search after two more sets of bones were discovered.

They will be looking beyond Suffolk County to Nassau County in the west, after more remains were found on Monday.

The sets of bones, belonging to 10 individuals suspected of being victims of the killer, have yet to be tested to determine if they are human remains.

Police believe the killings could be the work of a single individual, perhaps working in law enforcement.

Recently, the bodies of eight victims have turned up near the beaches of Suffolk County, and officials are saying a serial killer who preys mostly on women working as prostitutes is the likely suspect.

Thomas Krumpter, acting Nassau County police commissioner, announced the latest grisly discovery on Monday.

"At approximately 11:20am (15:20GMT) a state trooper using a cadaver dog did locate some bones on the Ocean Parkway on the north side, the bay side," he said, adding that the bones are being sent for tests to determine whether they are of human origin.

Although the area where the bones were found on Monday is in another county, it is close to Gilgo Beach in Suffolk County where most of the other remains have been discovered.

About 50 people took part in Monday's search, and local leaders implored the public to come forward with any information that might lead to an arrest.

"Collectively we want to bring to justice this animal that has obviously taken the lives of a number of people," said Edward Mangano of the Nassau County Executive.

"We encourage anyone that has any information to call our hotline, 1-800-244-TIPS, 1-800-244 TIPS, bring this animal to justice."

The area searched on Monday along Ocean Parkway is near Jones Beach, a popular sun bathing and swimming destination for millions of New Yorkers each summer.

Source: Agencies