Police searched in North Sea Friday with a K-9 unit at the location of an unsolved 1993 murder.

Sources tell News 12 the multiagency search has now expanded to an area in North Sea, where the body of Sandra Costilla was found in 1993, a case that remains unsolved.

In the past, convicted murderer John Bittrolff has been tied to the death of Costilla but was never charged.

Bittrolff, a former Manorville carpenter, is currently serving a 50-year-to-life sentence for the strangulation murders of Rita Tangredi and Colleen McNamee.

As News 12 has reported, law enforcement had already been searching an area in Manorville this week, near where Bittrolff used to live.

Officials would not say if the search in North Sea has any association to the Manorville search. However, Suffolk District Attorney Ray Tierney has stated previously that Bittrolff has nothing to do with the Gilgo Beach serial killer investigations.