Paul Tully, a member of the local council in Ipswich City in Queensland, has found the image of what appears to be a knife-wielding man on the gravestone of Walter Thomas Porriott in Toowong Cemetery, The Brisbane Times reports.

Porriott was in London at the time that five prostitutes were stabbed, and left the city not long after the series of killings, Tully says.

The first victim, Mary Ann Nichols, known as Polly, was killed Aug. 31, 1888. Four more women died through November, all in Whitechapel, a poor area of London's East End.

Tully, who is writing a book about the case, said Porriott was a bigamist and a thief as well as a killer. He was sentenced to prison for manslaughter in Britain in 1940 and died Aug. 29, 1952.

"This guy was a conman and a killer and was around Whitechapel at the time of the killings and could well have been the world's first recognized serial killer," Tully said.

Various theories have been floated about Jack the Ripper. One is that he was a member of the British royal family or some other powerful person who was protected by police.