He is the prime suspect in the disappearance of Simon Parkes, another young Royal Navy sailor who also vanished on 12 December from Gibraltar while Grimson was docked in the area.
Grimson joined the Royal Navy in 1978 and by the time of his conviction for murder, he had achieved the rank of Petty Officer (PO).
He had served aboard HMS Illustrious and was a trainer in fire fighting techniques whilst based at HMNB Portsmouth.
[2] Whilst being questioned by police, Grimson admitted that he scoured the ranks of trainees and cadets (that passed through HMS Excellent on the courses that he instructed on) so that he could dominate and kill the best looking ones.
At the time of his murder, he was working as a barman in the Hogs Head pub in Portsmouth and had met up with Grimson in a nightclub called Joanna's in the town.
In the morning, Jenkins expressed his desire to leave and Grimson wished to recapture the same feeling of elation that he had when he murdered Wright the previous year.
[7] Grimson was convicted in 2001 of killing Nicholas Wright and Sion Jenkins and the judge recommended that he serve a minimum of 22 years but also that he should never be released.
[11] In 2005, the BBC broadcast two programmes (The Search for Simon Parkes & October's edition of Crimewatch) which prompted Grimson to complain through his solicitor to Ofcom.
[15] In 1998, Grimson was working at the Royal New Zealand Navy base of Devonport on an exchange programme of fire fighting training.
Whilst he was there, a 29-year-old female Japanese immigrant, Kayo Matsuzawa, was found dead and hidden in a fire alarm cupboard in a stairwell of a building in Auckland.
[18][19] As well as Grimson's links to unsolved murders being the subject of the two BBC programmes in 2005 (The Search for Simon Parkes and the October 2005 edition of Crimewatch), his case was also featured in a 2019 documentary as part of Crime+ Investigation's series Murdertown.