The Back Door Key - Bruce Highland, #5

An Air Force Sergeant finds himself washed up on a remote South Pacific island with no recollection of how he got there. A major corporate executive is blackmailed and kidnapped. A key staff member from a national intelligence agency fights to protect a dark and embarrassing secret. Their respective lives become intertwined as private detective Bruce Highland is brought in to find the kidnapper, except that what he discovers is a much deeper, darker, mosaic of high tech conspiracy and corruption.
The novel is the fifth in a series of action adventure novels featuring ace detective Bruce Highland, a private investigator and former military intelligence agent.