He eventually relocated to England, taking positions at the Tavistock Clinic and the London School of Economics.
[4] Abrahamsen's paper, A Study of Lee Harvey Oswald: Psychological Capability of Murder, was published in the Bulletin of the New York Academy of Medicine, in October 1967.
[5] Abrahamsen's expertise in psychopathology was enlisted by authorities during the notorious Son of Sam serial murder case: when the killer, David Berkowitz, was finally in custody, Abrahamsen was directed by the Brooklyn District Attorney to evaluate his ability to stand trial.
Abrahamsen continued to examine Berkowitz in jail, and ultimately documented his life in Confessions of Son of Sam (1985).
[4] Abrahamsen suspected Prince Albert Victor and James Kenneth Stephen worked as a collaborating team to commit the Jack the Ripper murders.