Crime Immemorial

Seventeen-year-old Heidi Mnilk was German but was living in London, England, working as an au pair. On Monday, July 9th, 1973, she was riding on a train when she was approached and stabbed by an unknown attacker and thrown out of the carriage onto the tracks between the London Bridge and New Cross stations, near Catford.

During the investigation, it was found that four months earlier, a man approached a woman riding on the train along the same route, held a knife to her throat, asked if she was German, and then informed her that he hated all Germans, especially women. Though this victim survived her ordeal, the modus operandi seemed too coincidental to ignore.

There has been rampant speculation that Heidi Mnilk was murdered by prolific serial killer and neo-Nazi Patrick Mackay (also known as David Groves). Mackay was ultimately convicted of three counts of manslaughter in November of 1975; he killed two elderly women—Isabella Griffith and Adele Price—in February of 1974 and March of 1975, respectively, and also murdered a priest, Father Anthony Crean, with an ax in March of 1975.

After his capture, Mackay allegedly confessed to other inmates that he had killed six additional people, and his accounts of the unsolved murders largely matched the details of the actual crimes. One of these cases was the slaying of Heidi Mnilk.

When confronted with the information, however, Mackay denied killing anyone but the three victims he was convicted for, and one other man who he had thrown off a bridge in January of 1974.

Authorities launched new investigations into the unsolved crimes Mackay was suspected of in 2020, but no new evidence could be found linking him to the murder of Heidi Mnilk or the other victims. Mackay remains in prison as of this writing, and Heidi Mnilk’s murder is still unsolved.