Carl Edward ’Ed’ Brennick was 31 and living in Poway, California, when he disappeared during a scuba dive off La Jolla Shores on July 28, 1992. That morning he and longtime friend and diving partner Scott Lansinger set out for an ambitious descent into the La Jolla submarine canyon, planning to reach about 250 feet — far deeper than either had ever gone on compressed air. They were last seen around noon and never resurfaced.

Rescuers found the men’s vehicle in the beach parking area and two full scuba tanks inside, suggesting they entered the water for their first planned dive and did not return. Lifeguards and Coast Guard personnel conducted searches without locating either man, and no remains or conclusive physical evidence were recovered. Brennick, a dive-master, carpenter and avid outdoorsman, was engaged and his fiancée was about eight months pregnant at the time.

What details about that final dive or the men’s preparations might still help explain what happened beneath the canyon?