This short series of spooky mysteries for children featuring Sherlock Holmes was originally published in Australia in the 1990s. There are only three books in the series, and it isn’t easy to find copies now in the US. I have my copy because I bought it at a mystery book store in the 1990s. Reviews of the books on Amazon say that the series is somewhat mediocre because the supernatural themes and Christian morals are out-of-character for the original series and characters.
Like the original Sherlock Holmes stories, this series takes place in the Victorian era.
The series was written by Kel Richards.
Books in the Series:

The Curse of the Pharaohs (1997)
A dying Egyptologist believes that he will come back from the dead because of a mystical diamond, but who wants him dead in the first place?
The Headless Monk (1997)
A lighthouse keeper and his family are terrified by the ghost of a headless monk that seems to be seeking a hidden treasure.
The Vampire Serpent (1997)
Bodies are found, drained of blood, apparently the victims of a vampiric creature, and Holmes may be in danger of becoming a victim himself!