The Vanishing Investigator is a 1983 role-playing game adventure for Gangbusters published by TSR.
The Vanishing Investigator is an adventure scenario in which the player characters join the search for a senator and his family who went missing just prior to his Senate Committee on Organized Crime hearings.
[1] Jerry Epperson reviewed The Vanishing Investigator in Space Gamer No.
[1] Epperson commented that "If you are looking for a well-executed mystery, this one has all the elements, but is more of a guided tour than a 'whodunit.'
That's why Vanishing Investigator gets only a qualified recommendation.