Deputies from the San Marcos Sheriff's Station responded to the location and secured the scene. Sheriff's homicide detectives responded and assumed the primary investigative responsibility.
Helicopter video showed an area of open space near the lake shore surrounded by yellow tape. Several deputies could be see inside the taped area at about 11:15 a.m.
Detectives suspect the remains found today may belong to a missing person, whose partial remains were found nearby in October of 2015.
The skull may be related to human remains that were found in the general area last year, Nelson said. In that case, a woman was walking her dog when she came across the partial skeleton. She found the bones on Oct. 17, 2015, near the 19900 block of Lake Drive.
Those remains were identified as belonging to San Diego resident Marisol Lopez, age 30.
In 2015 the Medical Examiner's Office was unable to determine the cause or manner of death.
The Medical Examiner's Office will examine the remains found today and try to determine the identity of the victim as well as the cause and manner of death.