helicopters near the DMZ. The first report stated that four helicopters had been detected and were proceeding toward Tiger Island, just off the North Vietnamese coast at an altitude of . These spotters observed the aircraft visually, using Starlight Scopes and by radar. Over the course of the night, Air Force pilots reported 19 additional helicopter sightings. On this same evening the guided missile heavy cruiser , operating near the DMZ, also began reporting helicopter activity in the vicinity of Bến Hải, Cap Lay and Tiger Island. At 00:10 on the 16th, an unidentified aircraft fired three rockets or missiles at Boston, but none hit the vessel. At 01:00 on 16 June 1968 in the same area, PCF-19 was struck by two missiles, one struck the cabin just below the pilothouse on the port side, the other hit the engine room. The boat sank in four minutes. Four of its crewmen were killed, and two others badly injured. The remaining crew managed to swim free from the sinking craft and cling to a life raft until arrived on scene at 01:30. As soon as the survivors were on board, Point Dume departed the scene to drop them off at the Cua Viet Base for a medevac to Danang. In the meantime, the crew of PCF-12, which had arrived on the scene at 01:50 to continue the search for survivors, noticed illumination rounds being fired that were not their own. Opting to investigate, the officer in charge ordered the boat to speed to the Cua Viet River. When PCF-12 was from the river mouth, crewmembers observed two sets of aircraft lights off the port and starboard beam, about away and above the water. The boat commander immediately got on the radio and requested permission to engage the aircraft. At 02:25, PCF-12 received a single rocket from seaward at a low trajectory. The rocket passed a couple of feet over the main cabin and exploded in the water ten feet from the boat. PCF-12 came about, increased speed and moved away from the kill zone while bringing its .50-caliber guns to bear against an aerial target hovering at with lights blinking. The aircraft decreased altitude and turned off its lights. After a short time, PCF-12 stopped to observe the scene and saw two aircraft appeared off its beams again with lights on. The boat commander contacted the marine observer and inquired about