Sodeman was born on December 12, 1899 in Victoria. He worked as a labourer, was married with a daughter, and was a heavy drinker with a record of minor offences from his youth.
Between November 1930 and January 1935 he killed four girls in and around Melbourne: Mena Griffiths, twelve; Hazel Wilson, sixteen; Ethel Belshaw, twelve; and June Rushmer, six. Each was strangled, bound with cord, and left in the open. The gaps between the killings, four years, then months, were long enough that the series was not treated as one until the last. The Melbourne press called him the School-girl Strangler.
He was arrested in December 1935 after being seen near where June Rushmer disappeared, and he confessed to all four. He said he had been drinking heavily before each and had no memory of what he had done.
He was tried in February 1936. The defence was insanity, supported by evidence that his father and grandfather had both died in psychiatric institutions. The jury rejected it and he was hanged at Pentridge prison on June 1, 1936.
A post-mortem examination of his brain found leptomeningitis, inflammation of the membranes, which the pathologist considered consistent with his account that alcohol had produced episodes of uncontrolled violence. The finding came after the execution and has been discussed in Australian legal and medical writing ever since. It changed nothing for him and is the reason the case is still cited.