Up until the early 1990s Mackenzie himself was a prime suspect but recent research suggests that he himself was probably not responsible for the massacre, since he was in Sydney at the time. The Mackenzies were admonished for this mass killing by Attorney-General John Hubert Plunkett (1802–1869), who threatened prosecution if an official complaint was lodged. Though MacKenzie's involvement was never verified, this incident was mentioned in a select committee in 1861 and repeated by W. Coote in 1867. The English overseer disappeared upon Mackenzie's return. Mackenzie organised the conspiracy of silence to protect the Englishman.