Sherlock Holmes, Inspector Marsh and Insepctor Lestrade

Over the course of a year there had been eighty six murders committed in the greater London area. Nine of these murders had gone unsolved. Inspector Lestrade solved twice as his collegue Inspector Marsh, who in turn, had solved only a quarter of those solved by Sherlock Holmes. Can you deduce how many murders Inspector Marsh had solved? Credit- More Sherlock Holmes Puzzles Book by Tom Bullimore