Notwithstanding that a large number of detectives and plain clothes constables were engaged yesterday on investigating various matters supposed to be connected with the murder of the woman Nicholls in Whitechapel, nothing had occurred up to midnight to throw any light upon the affair. There is little doubt that the detectives in charge of the case have a clue to which they attach no little importance. The officers speak in a very confident manner of the result of their recent investigations, and continued to pursue their operations until a very late hour. Amongst the many persons who are under observation is a very notorious character, to whose movements considerable importance is attached, and the police are also acquainted with the movements of a seafaring man, who is alleged to have already stood his trial for a serious crime. This man, it is stated, has been seen in the neighbourhood with a large sheath knife, and he is known to be a frequenter of common lodging houses. Not much importance is, however, attached to this individual, but nevertheless he is being kept in view.