Series:

Three Investigators Mystery S.

4 primary works

Book 1

Cover of Secret of Terror Castle

Secret of Terror Castle

by Robert Arthur

Published October 1967

Book 3

Cover of Whispering Mummy

Whispering Mummy

by Robert Arthur

Published 9 April 1992

Book 5

Cover of The Vanishing Treasure

The Vanishing Treasure

by Robert Arthur

Published 14 May 1992

Book 6

Cover of Secret of Skeleton Island

Secret of Skeleton Island

by Robert Arthur

Published 27 July 1970
The Three Investigators are assisted by a Greek youth as they search for clues to a mysterious thief on an island once inhabited by pirates.