NCIS Case Report: Unidentified Submersible Vessel Observed by US Navy Members

This document is a collection of NCIS case reports and correspondence regarding a Force Protection operation for the USS Peleliu Amphibious Readiness Group (PELARG) during 2012 and 2013. The primary focus of the declassified material is a special inquiry into an unidentified submersible vessel observed by a helicopter crew from Helicopter Sea Combat Squadron 21 (HSC-21) on June 15, 2012. While conducting search and rescue training off the coast of Cabo San Lucas, Mexico, the crew of an MH-60S helicopter observed an object in the wake of the USS Peleliu. The crew reported seeing multiple infrared beacons visible only through night vision goggles and a shape in the water they believed to be a submarine. The object was estimated to be 40-60 feet long and was observed for approximately 15 minutes. The crew reported hearing unencrypted radio communications in a foreign language, described as eastern European, during the encounter. Despite attempts to capture video or photographic evidence using the aircraft's Forward Looking Infrared (FLIR) system, the crew was unsuccessful. Subsequent analysis by the Office of Naval Intelligence (ONI) considered whether the object was a self-propelled semi-submersible vessel (SPSS), a type of craft often used for maritime smuggling. However, investigators noted that the sighting occurred approximately 2,500 nautical miles from known transit zones, making such an identification unusual. The investigation also noted that electronic intelligence (ELINT) systems detected two navigational radar transmitters in the vicinity, which were activated and deactivated in a manner consistent with potential smuggling activity. The case file also contains reports on various other criminal investigations conducted by NCIS during the PELARG deployment, including allegations of sexual assault, hazing, and drug interdictions by other naval vessels. The document concludes that the investigation into the unidentified submersible was closed after all leads were exhausted, with the final assessment remaining inconclusive regarding the exact nature of the craft.