NACIMIENTO — The death of a woman at Lake Nacimiento this month is under investigation.

Monterey County officials say park rangers were called to reports of CPR being performed on a person on a boat near the lake’s dam on Sunday, July 9.

Initial reports were that the woman, identified by the San Luis Obispo County Sheriff’s Office as Luz Maria Ruiz, 57, of Santa Barbara, fell off a tube being towed behind a “personal watercraft.”

Reports say a private boater who is also an EMT reportedly recovered the woman and began CPR. Once rangers arrived, Ruiz was moved to their patrol boat and taken to the main launch ramp at the Lake Nacimiento Resort as CPR continued to be performed.

Additional agencies also responded, but Ruiz was pronounced dead at the scene.

County officials say her cause of death has not yet been determined, adding that the investigation, which is being conducted by Monterey County Park Rangers, is still ongoing.