Peter D. Greene (1970 to February 12, 1971)
Dan Hamilton (February 15, 1971 to April 1972)
Former junior executive working for Stanley "Stan" Norris
Katherine "Kit" Vested (sister; deceased)
Karen Martin (engaged)
Plotted to wrest control of Liberty Airlines and force Stanley Norris out by illegal stock manipulation 
Threatened to kill Stanley Norris [September 1971]
Suspected of murdering Stanley Norris (innocent) [September 1971 - March 1972]
David Vested was introduced as the older brother of the emotionally unstable Cedars hospital nurse Katherine "Kit" Vested. David himself was also not the most stable of men either, usually very angry and brooding. However, in many respect, David's brooding was understandable. Kit had recently been dumped by David's boss, rich businessman, Stanley Norris. Although David was resentful of Stanley's treatment of Kit, David continued to play the worshipful employee to the hilt. However, in reality, David's resentment had developed into full-blown hatred! At the same time, Stanley himself was unaware that his glamorous ex-lover, Karen Martin, had jilted him because she was really in love with David Vested.
By 1971, David had asked Karen to marry him, but Karen off accepting his marriage proposal. In the meantime, David was very disconcerted when Kit tried to commit suicide and ended up in Cedars hospital. At the same time, Kit herself was becoming increasingly worried about her brother, who was consumed by ambition and his brewing hatred of Stanley. David knew that Stanley was stripping some of his companies of ready cash in order to bolster Liberty Airlines, which was going through a rough period. David plotted to gain the controlling shares of Liberty, and at an opportune moment, force Stanley out and marry Karen Martin. Nearly at the same time that Karen finally gave in and accepted David's marriage proposal, Stanley who was a shrewd business man, knew someone was out to destroy him. After discovering phone calls from David to Karen, Stanley realized David was the enemy. Stanley then shamed Karen into betraying David by signing over a block of her shares. By now it was September 1971, and David threatened to kill Stanley over what he had done to Karen!
A couple of nights later, one of David's colleagues, Gil Mehren, found Stanley’s new wife, Leslie Norris, standing next to a very dead Stanley -- with the gun nearby! Although she professed her innocence, Leslie was arrested and put on trial for Stanley's murder. However, the suspects in Stanley's murder were many and included both David Vested and Karen Martin. By the spring of 1972 though, Mike had pieced together that the murderer was instead the mother of one of Stanley's secretaries, Marion Conway, and this cleared David and Karen. Meanwhile, fed up with David's vengeful, but failed, quest to overtake Stanley's business empire, Karen jilted him and gave back his engagement ring. Karen and David blew out of town separately, leaving David's fragile sister, Kit, to salvage her sad life.