Inspector Tanner

Austin Ponson

Austin is a key suspect and later ally, interacting heavily with Tanner during the investigation.

Cosgrove Ponson

Cosgrove is a primary suspect, and his frequent interactions with Tanner reflect intense interrogation and scrutiny.

Sir William Ponson

Tanner investigates Sir William as the patriarch of the family, often seeking his cooperation or questioning his motives.

Lois Drew

Tanner interviews Lois as a witness and potential suspect, probing her connection to the Ponson family.

William Douglas

Tanner interacts with William Douglas as part of the investigation, likely as a witness or person of interest.

Jimmy Daunt

Tanner questions Jimmy Daunt as a suspect, with frequent interactions suggesting intense interrogation.

Tom Dale

Tanner works with Tom Dale as a colleague or subordinate in the investigation.

Sergeant Longwell

Tanner and Longwell are police colleagues, with Longwell assisting Tanner in the investigation.

Sir William Ponson

Tanner investigates Sir William as the patriarch of the family, often seeking his cooperation or questioning his motives.

Cosgrove Ponson

Cosgrove is a primary suspect, and his frequent interactions with Tanner reflect intense interrogation and scrutiny.

Austin Ponson

Austin is a key suspect and later ally, interacting heavily with Tanner during the investigation.

Tom Dale

Tanner works with Tom Dale as a colleague or subordinate in the investigation.

A Sinister Suggestion

Assigned to the case; decides to keep the murder evidence secret.

III: Hoaxed?

Conducts the interview with Austin, searches the riverbanks, and observes Austin's fear at the inquest.

IV: Inspector Tanner Grows Suspicious

Leads the investigation; interviews family and servants, examines Sir William's papers, discovers mysterious 'X' cheques, and plans to test Austin's alibi.

Inspector Tanner Becomes Convinced

Reviews the case, becomes convinced of Austin's innocence, interviews Lois Drew, and decides to investigate Cosgrove Ponson.

What Cosgrove Had to Tell

Travels to London, searches Cosgrove's rooms, follows Cosgrove, and confronts him at the Huntingdon Club.

VII: Cosgrove's Trip North

Investigates Cosgrove's alibi, interviews the butler and Miss Belcher, and consults a tobacconist about cigarette ends.

Tanner Finds Himself Duped

Leads the investigation, attends the inquest, follows up on Sir William's London visits, interviews Lucy Penrose and Herbert Potts, and ultimately arrests Austin Ponson before beginning to doubt the case.

IX: Lois Drew Takes a Hand

Receives Lois's letter; is asked by Jimmy Daunt to keep Lois's name out of the case; agrees not to make the engagement public unless necessary.

X: A Woman's Wit

Shares details of Cosgrove's alibi with Daunt in confidence, believing it to be conclusive.

A Fresh Start

Tanner leads the investigation, retracing Sir William's steps and uncovering the secret meeting and the mysterious Douglas.

A Stern Chase

Travels to Yelverton to arrest William Douglas, is tricked by Douglas's escape, discovers incriminating boots, organizes a police search, and eventually arrests Douglas in Lisbon.

XIII: Blackmail?

Returns to Scotland Yard, meets with Daunt, learns Cosgrove's alibi is fake, recounts his Portuguese expedition and arrest of William Douglas, and theorizes about a conspiracy or blackmail.

A Dramatic Discovery

Leads the investigation, interviews Mr. Clayton, and orchestrates the confrontation that reveals Tom Dale's identity.

Conclusion

Doubts Austin's statement but is convinced after searching examination of details.