Interesting to note that a series of questions to a cricket writer includes one about whether or not Jack was a cricketer. From the article:

Is it true that the notorious murderer Jack the Ripper was a cricketer? asked Ken Mountford from London
The identity of "Jack the Ripper", who carried out a series of grisly murders in London's East End in 1888, has never been conclusively proved. Various suspects have been put forward over the years, and one of them was indeed a reputable cricketer - Montague Druitt, who played in trial matches while up at Oxford without getting into the university side, was a member of MCC, and also played for the prominent London club Blackheath. A bowler, he took five wickets for Bournemouth against the touring Parsees from India in 1888. Druitt was found drowned in December of that year, a month after the last confirmed "Ripper" murder.