 In 1991, he published the standard biography of the great Scottish criminologist William Roughead, with extensive and valuable comments on the celebrated cases covered by Roughead during his lifetime.His next crime book was a full-length study of the Oscar Slater case, and in 2002, he published the standard account of the fascinating Cheltenham torso mystery.In 2013, he published a much extended "Definitive Casebook on Jack the Ripper", containing a full historiography of this celebrated case.