Complex sentence: In 1889, while investigating the Whitechapel murders Sergeant Thick was named in letters by H.T. Hazelwood as as a prospective perpetrator, to wit I have very good grounds to believe that the person who has committed the Whitechapel Murders is a member of the police force.
Split into simpler sentences: In 1889, while investigating the Whitechapel murders Sergeant Thick was named in a letter by H.T. Hazelwood as as a prospective perpetrator. To wit I have very good grounds to believe that the person who has committed the Whitechapel Murders is a member of the police force.