Frederick Porter Wensley OBE KPM (28 March 1865 – 4 December 1949) served as a British police officer from 1888 until 1929, reaching the rank of chief constable of the Scotland Yard Criminal Investigation Department (CID).

Serving in Whitechapel for part of his career, he was involved in street patrols during the investigation of the Jack the Ripper murders,[2] details of which he would later publish in his memoirs in 1931.

He first gained public attention in 1896 when he was responsible for capturing a burglar and murderer named William Seaman in a fight in Whitechapel in front of a crowd.

[1] On 1 June 1920, Chief Inspector Wensley was made a member of the Order of the British Empire (MBE),[9] and in December 1921, now a Superintendent, he became head of the CID at Scotland Yard.

In March 1922, Wensley was appointed to the new post of Chief Constable of the CID, having overall command of some 800 detectives in the London area, including 150 working directly from Scotland Yard.

In the "Clapham Common" Mystery of 1911, linked by the press to the Sidney Street siege,[11] the chief suspect, Steinie Morrison may have been observed unfairly by witnesses shepherded by Wensley.

This case was notable because Mrs Thompson appears never to have been linked to the murder committed by her lover, except for letters she wrote to Bywaters suggesting she was trying to poison Percy.

He interviewed Gerard's lover, Louis Voisin, and arrested him after discovering that he misspelt "bloody" in the same way as the murderer, who had left "blodie Belgium" at the crime scene.

[3]Wensley also agreed with commonly held theories that the police were never sure of their suspects, he commenting "Officially, only five (with a possible sixth) murders were attributed to Jack the Ripper.