He was given the job following a reference from Lord Trenchard, Marshall of the Royal Air Force and Commissioner of the Metropolitan Police.
Dennis was appointed Chief Inspector of Police with the British Municipal Council, Tientsin arriving to take up his duties in July 1934 with the new rank of DCI.
During his time as chief of the Tientsin police Dennis investigated the infamous Pamela Werner murder in January 1937 in Beijing.
Eventually the Tientisin police were ordered by Sir Robert Craigie, Britain’s Ambassador in Tokyo, to hand over the accused men.
Eventually, in early August, the Swiss Consul in Tientsin managed to secure Dennis’s release and repatriation.
In a greatly weakened state he was taken to Shanghai and put aboard an overcrowded evacuation ship (the Kamakura Maru)[1] to Lourenço Marques in Portuguese East Africa.