The Strange Vice of Mrs Wardh

Carol Brandt was killed by Neil Wardh, Julie's own husband. Neil disguised himself as the razor killer to murder Carol and frame the serial murders, using the same straight razor method. This was part of a larger conspiracy between Neil and George to eliminate people standing in the way of their plan.

Earlier at the party, Neil suspiciously arrived at just the right moment to confront Jean outside, showing his pattern of strategic appearances.

Neil Wardh and George Corro formed a murder conspiracy with two objectives: Carol's death would make George the sole heir to his wealthy uncle's fortune, while Julie's death would trigger a massive insurance payout to save Neil from bankruptcy. They provided each other alibis and used the razor killer's crimes as cover. Neil killed Carol in the park, while George attempted to kill Julie in the parking garage and later hired Jean to finish the job.

The note demanding money to keep the affair secret was actually part of the conspiracy to isolate Julie and create a motive for her murder.

Jean faked his death as part of George and Neil's conspiracy. After the real razor killer was dead and could no longer be used as a cover for their murders, they needed Jean to pose as the killer and eliminate Julie in Spain. George and Neil staged Jean's bloody bathtub death to make it appear the razor killer had targeted him, when in reality he was alive and working with them.

Jean had an airtight alibi when Julie accused him of Carol's murder, indicating he was protected by someone with authority.

Jean was the one stalking Julie in Spain. After faking his death, Jean was sent to Spain to murder Julie and make it appear as a suicide. He sent her threatening notes signed "Jean" to heighten her paranoia and psychological state before the final attack. This explains why Julie was terrorized despite the real razor killer already being dead in Vienna.

The note signed "Jean" arrived right after Julie read that the razor killer was a stranger, making her realize someone from her circle was still hunting her.

Julie survived because the doctor who arrived with George was prepared for foul play. The police had grown suspicious when Carol's murder didn't fit the razor killer's usual pattern, so they rigged the scenario. The doctor was able to save Julie from the carbon monoxide poisoning, and the police faked her death certificate to lure George and Neil into a trap.

The police noted early on that Carol's murder didn't align with the razor killer's modus operandi, triggering their investigation.

The real razor killer was a separate maniac killing women with a straight razor in Vienna, unrelated to the conspiracy. He was eventually killed by one of his own intended victims in self-defense, which George and Neil used to their advantage, once the real killer was dead, they recruited Jean to continue the murder spree under their direction.

The razor killer's victims were all women, and his method was distinctive enough that Neil could mimic it for his own purposes.

Carol had to die because she was George's cousin and co-heir to their wealthy uncle's fortune. With Carol alive, George would only inherit half the estate. Her death made George the sole heir, providing the money needed to fund the conspiracy. This explains why Neil, who had no direct connection to Carol, committed the murder himself, to give George a clean inheritance.

At the party, Carol introduced George as her cousin who had just inherited with her, establishing their shared stake in the uncle's fortune.

George Corro was the attacker in the parking garage. He attacked Julie with a straight razor to make it appear the razor killer had targeted her, just as Neil had killed Carol. Julie managed to fight him off and escape, which forced the conspirators to change tactics and hire Jean to finish the job instead.

George's romantic pursuit of Julie was unusually aggressive and insistent from the beginning, suggesting ulterior motives beyond attraction.

The police grew suspicious because Carol's murder didn't match the real razor killer's pattern, he typically targeted women he stalked beforehand, whereas Carol was lured to the park by a blackmail call. This inconsistency led them to investigate Neil and George, ultimately allowing them to set up the fake death of Julie to trap the conspirators.

The police initially seemed ineffective, but they were quietly building their case by connecting the inconsistencies in the murder methods.

Neil was financially ruined and facing bankruptcy. Julie's life insurance policy would pay out a massive sum upon her death, providing Neil with the funds to escape his debts. This financial motive explains why Neil, despite seeming protective at times, was actually plotting his wife's murder throughout the film.

Neil was often away from home, and his emotional distance from Julie suggested he was detached from the marriage for reasons beyond his diplomatic work.

George killed Jean because he was a liability who could testify against him. After successfully framing Jean for Julie's supposed suicide, Jean demanded his promised payment and a fake passport to flee to Rio de Janeiro. George realized Jean could expose the entire conspiracy if paid off, so he shot him dead and staged the death as another suicide to eliminate the witness.

Jean was introduced as a dangerous, untrustworthy figure who had previously mistreated Julie, establishing his character as someone who would eventually demand payment.