See I. W. Van Noppen, Stoneman's Last Raid (1961).
The Stoneman was credited with thirteen murders over six months (the first in June 1989), but it was never established whether the crimes were the handiwork of one person or a group of individuals. The Calcutta police also failed to resolve whether any of the crimes was committed as a copycat murder. To date, no one has been sentenced for these crimes, making this one of the greatest unsolved mysteries plaguing modern metropolitan Indian police forces.
A stroke of luck seemed to come the police's way when a homeless waiter survived a brutal attack and managed to escape being bludgeoned to death. However, in the dimly lit area of Sion where he was sleeping, he had not been able to get a good look at his assailant, and what seemed like a big break came to naught.
Shortly afterwards, in 1987, a ragpicker was hacked to death in the adjoining suburb of Matunga. Even though the police and the media were quick to label this the handiwork of the same person, no evidence to link this crime with the others was ever found.
As mysteriously as the killings had started, by the middle of 1987, they stopped.
The first victim in Calcutta died from injuries to the head in June 1989. Twelve more would die in the next six months as panic gripped the city. All of the murdered were homeless pavement-dwellers who slept alone in dimly lit areas of the city.
Because the murderer killed victims by dropping a heavy stone or concrete slab, the police guessed that the assailant was probably a tall, well-built male. However, in the complete absence of any eyewitness or survivor, no clear-cut leads were available.
Massive deployments of police in various parts of the city at night were resorted to, and numerous arrests were made. After a spell of arrests in which a handful of "suspicious persons" were rounded up for questioning, the killings stopped. However, since there was no incriminating evidence, no "smoking gun" so to speak, all those summarily arrested had to be released. One of those temporarily summoned was not mentally fit to be questioned, but the media and police were quick to note that the killings had ceased.
To date, the crimes remain unsolved.