That Woman Opposite

Maurice Lawes witnesses the Gendarme's murder while at his window. The killer spots Lawes looking down and realizes he has been seen, meaning Lawes could identify him. This makes Lawes a threat who must be eliminated to prevent identification, which is why he is murdered the following evening.

Lawes' position at the window during the first murder directly creates the motive for his own death.

Toby Lawes has been embezzling funds from his father's estate to pay off a blackmailing ex-mistress. This financial desperation provides Toby with a strong motive to harm Maurice, either to cover up the embezzlement or to access his father's wealth before the thefts are discovered.

Toby's financial troubles are established early, making him a prime suspect from the start of the investigation.

Ned Atwood, Eve's ex-husband, shows particular interest in a rare snuffbox from Maurice Lawes' personal collection. This snuffbox goes missing, linking Ned to both a potential burglary and possibly to the murder itself, suggesting the item holds significant value beyond its ordinary worth.

Ned's specific interest in the snuffbox early in the investigation hints at its central role in the crime.

Eve Atwood, who lives directly opposite the murder scene and is engaged to Toby Lawes, is found in possession of bloodstained clothing she cannot satisfactorily explain. This evidence places her under intense scrutiny and raises the possibility she was either an accomplice or somehow involved in the murder, either acting with Toby or Ned.

Eve's proximity to the crime scene makes her mysterious evidence particularly damning.

Investigators initially believe Maurice Lawes was killed to prevent him from identifying the killer of the Gendarme. This theory treats the murder as a cover-up rather than a straightforward burglary, opening the case to multiple suspects who might have wanted to silence Lawes.

The witnessed first murder establishes the cover-up motive that drives the entire investigation.

Dermot Kinross, a private insurance investigator working with local police, methodically weighs alibis, financial motives, and the strange missing snuffbox to piece together the actual sequence of events. He sifts through lies and partial truths to distinguish genuine motives from misdirection.

The investigation's careful, methodical approach gradually reveals how the crimes are connected.

Eve Atwood is engaged to Toby Lawes but is also the ex-wife of Ned Atwood. This positions her at the center of two key suspects - her current fiancé and her former husband - leading Kinross to consider whether she acted as an accomplice to either man or became entangled in events she didn't fully understand.

Eve's dual connection to Toby and Ned creates the triangular relationship that drives much of the suspicion.

The first murder is the Gendarme killed in town, which Maurice Lawes witnesses. Because Lawes sees the killer, the killer is compelled to murder Lawes the following evening to eliminate the only witness who could identify him, creating a connected chain of crimes rather than two separate incidents.

The first murder's witness creates the direct cause for the second.