Maurice Grosse (6 March 1919 – 14 October 2006) was a British inventor and engineer who, in later life, became one of the best-known paranormal investigators associated with the Society for Psychical Research, principally through his investigation of the Enfield Poltergeist between 1977 and 1979.
Early life and war service
Grosse was born in Hackney, London, to Jewish immigrant parents from Romania and Russia, and was educated at Regent Street Polytechnic before training in commercial design. During the Second World War, he served with the Royal Artillery and was among those evacuated from Dunkirk in June 1940. Commissioned in 1941, he spent the rest of the war responsible for the guarding and welfare of Italian prisoners of war. In 1944, he married Betty Grosse, and the couple had three children, including a daughter, Janet.
Career as an inventor
After the war, Grosse built a successful career as an inventor, filing his first mechanical patent in 1945. His best-known invention was the rotating advertising billboard, now a familiar sight at British bus stops. In 1961, he founded his own design and engineering consultancy, which went on to launch numerous patents internationally.
Turn to psychical research
Grosse's move into psychical research followed personal tragedy: his daughter Janet was killed in a motorcycle accident in August 1976. In the aftermath, members of his family reported a series of coincidences and experiences they considered psychic in nature, prompting Grosse to join the Society for Psychical Research the following year. He quickly became active within the Society, being co-opted onto its Council in 1979, appointed assistant honorary treasurer the year after, and going on to chair its Spontaneous Cases Committee for over two decades from 1981. He was also a life member of The Ghost Club.
The Enfield Poltergeist
Grosse became the Enfield Poltergeist's principal investigator after the case reached the SPR in September 1977, visiting the Hodgson family's house for the first time on 5 September that year and remaining closely involved for over two years. Given the striking coincidence that the case centred on a girl named Janet — sharing his own late daughter's name — Grosse brought an unusually personal dedication to the investigation alongside his engineer's methodical approach, maintaining detailed logs and tape recordings and using what technology was then available to document the case. He approached the work with a firm conviction that sustained, careful fieldwork on genuine spontaneous cases was essential to psychical research, and could not be substituted by sceptical argument from an armchair.
Later investigations
Grosse continued investigating cases well beyond Enfield. In 1995, he attended a vigil at Charlton House during which a piece of crockery was reported to have materialised and shattered, and in 2000 he recorded what he described as poltergeist knockings at a family home in north London. He also investigated numerous claimed cases of precognition and compiled an extensive personal collection of alleged psychic photography, continuing this work up until the summer of 2006.
Death and legacy
Grosse died on 14 October 2006 in London. He appeared posthumously in Channel 4's documentary Interview with a Poltergeist, broadcast on 6 March 2007, and has since been portrayed on screen by Timothy Spall in the 2015 Sky Living miniseries The Enfield Haunting and by Simon McBurney in the 2016 film The Conjuring 2.