Slayer's End is a case featured in Criminal Case as the twenty-fourth case of Mysteries of the Past (Season 4) and the one-hundred ninety-fifth case overall. It is the final case to take place in the Sinner's End district of Concordia.
During the investigation, Constable Ramirez had found the train car serving as the Slayer's hideout. Judge Lawson was then proven to have met up with Fiona, forcing the Flying Squad to flag him as a suspect. Later, Maddie arrested both Finley Flanagan and Vittorio Capecchi after the two shot each other. The team then found enough evidence to arrest Finley for his sister's murder.
After accidentally confessing to the murder, Finley said that he had taken care of his sister despite her bouts of criminal insanity. However, he could not help her when she started killing prostitutes. After she escaped custody and went to the opium den, she madly lashed out at Finley. Figuring out that Fiona was too far gone, he strangled her with a curtain rope out of mercy. In court, Judge Takakura took on the trial due to Judge Lawson's personal involvement in the case. He sentenced Finley to 25 years in Stonewall Prison.
After the trial, Finley asked Katherine Woolf and the player to help him relocate out of Stonewall because the Italian gang was running the prison. He told them to go to his office for proof, where they found an Irish inmate's call for help to Finley from the prison. After Vittorio refused to talk about Stonewall, the two searched the Flanagans' office again. There, they found a court document dismissing a case regarding the Italians' influence on the prison. Takakura said that the prosecution did not have enough evidence, but he speculated that Vittorio had paid the police to hide the evidence.
Meanwhile, Isaac and the player gave Marla de Paradis the Moulin Rose's key so she could buy the cabaret with the inheritance she got from her deceased fiancé. Later, Chief Wright then said that Finley was to remain in the Squad's holding cell until they made sure that there was no Italian influence in the prison. The Squad then went to Coyote Gorge to investigate Stonewall Prison.
- Fiona Flanagan (found dead in an opium den)
- Curtain String
- Finley Flanagan
- The killer uses Lavender Lust cream.
- The killer eats spaghetti.
- The killer smokes opium.
- The killer has blood type AB+.
- The killer wears a starched collar.
- Investigate Opium Den. (Clues: Silk Cushion, Fiona's Knife, Victim's Body; Victim identified: Fiona Flanagan)
- Examine Silk Cushion. (Result: Wood Shavings)
- Examine Wood Shavings. (Result: Wixon CC Pencil; New Suspect: Katherine Woolf)
- Interrogate Katherine Woolf about her presence at crime scene. (Prerequisite: Wixon CC Pencil identified under microscope; New Crime Scene Unlocked: The Flanagan Headquarters)
- Investigate The Flanagan Headquarters. (Prerequisite: Katherine interrogated; Clue: Locked Chest; New Suspect: Finley Flanagan)
- Interrogate Finley about his sister's escape and murder. (Prerequisite: The Flanagan Headquarters investigated)
- Examine Locked Chest. (Result: Open Chest)
- Examine Open Chest. (Result: Whip; New Suspect: Adrienna Brassiere)
- Find out why Adrienna was in the Flanagans' office. (Prerequisite: Whip found)
- Examine Fiona's Knife. (Result: Red Substance)
- Analyze Red Substance. (03:00:00; Attribute: The killer eats spaghetti)
- Autopsy Victim's Body. (18:00:00; Attribute: The killer uses Lavender Lust cream)
- Go to Chapter 2. (No stars)
- Investigate Scarlet Slayer's Hideout. (Available after unlocking Chapter 2; Clues: Sinner's End Map, Broken Metal Pieces, Barrel)
- Examine Sinner's End Map. (Result: Katherine's Map)
- Confront Katherine Woolf about Fiona's hideout. (Prerequisite: Katherine's Map unraveled; Profile updated: Katherine uses Lavender Lust cream and eats spaghetti)
- Examine Broken Metal Pieces. (Result: Copper Heart; New Suspect: Vittorio Capecchi)
- Question Vittorio Capecchi about the Kiss of Death sent to the victim. (Prerequisite: Copper Heart unraveled)
- Examine Barrel. (Result: Curtain String; Murder Weapon registered: Curtain String)
- Analyze Curtain String. (12:00:00; Attribute: The killer smokes opium; New Crime Scene Unlocked: Fiona's Desk)
- Investigate Fiona's Desk. (Prerequisite: Curtain String analyzed; Clues: Photograph [Unknown Woman], Whiskey Glasses)
- Examine Unknown Woman. (Result: Celia Barnes)
- Ask Adrienna about Celia Barnes. (Prerequisite: Celia Barnes identified; Profile updated: Adrienna smokes opium)
- Examine Whiskey Glasses. (Result: Fingerprints)
- Analyze Fingerprints. (12:00:00; New Suspect: Justin Lawson)
- Interrogate Judge Lawson about drinking whiskey with Fiona. (Prerequisite: Fingerprints analyzed; Profile updated: Justin uses Lavender Lust cream and eats spaghetti)
- Go to Chapter 3. (1 star)
- Investigate Hideout Corner. (Available after unlocking Chapter 3; Clues: Asylum Document, Rusty Safe, Broken Jewelry)
- Examine Asylum Document. (Result: Admission Details)
- Ask Finley how much he knew about his sister's actions. (Prerequisite: Admission Details unraveled; Profile updated: Finley uses Lavender Lust cream and smokes opium)
- Examine Rusty Safe. (Result: Pair of Bracelets)
- Analyze Pair of Bracelets. (09:00:00)
- Talk to Justin Lawson about his bride's killers. (Prerequisite: Pair of Bracelets analyzed; Profile updated: Justin smokes opium)
- Examine Broken Jewelry. (Result: Brooch)
- Ask Vittorio Capecchi about his brooch in Fiona's hideout. (Prerequisite: Brooch unraveled; Profiles updated: Vittorio eats spaghetti, Finley eats spaghetti)
- Profile updated: Katherine smokes opium.
- Investigate Den Lounge. (All tasks before must be done first; Clues: Opium Pipe, Torn Cloth)
- Examine Opium Pipe. (Result: Blood)
- Analyze Blood. (09:00:00; Attribute: The killer has blood type AB+)
- Examine Torn Cloth. (Result: White Substance)
- Analyze White Substance. (15:00:00; Attribute: The killer wears a starched collar)
- Take care of the killer now!
- Go to By Hook or by Crook (6/6). (No stars)
By Hook or by Crook (6/6)
- Assist Marla de Paradis. (Available after unlocking By Hook or by Crook; Reward: 20,000 Coins)
- Investigate Scarlet Slayer's Hideout. (Prerequisite: Marla interrogated; Clue: Crate of Whiskey)
- Examine Crate of Whiskey. (Result: Moulin Rose Key)
- Analyze Moulin Rose Key. (06:00:00)
- Give Marla de Paradis the key to the Moulin Rose. (Prerequisite: Moulin Rose Key analyzed; Reward: [MALE] Feather Top Hat, [FEMALE] Feather Headdress)
- See what Finley wants. (Available after unlocking By Hook or by Crook)
- Investigate The Flanagan Headquarters. (Prerequisite: Finley interrogated; Clue: Parcel)
- Examine Parcel. (Result: Message)
- Analyze Message. (09:00:00)
- Confront Vittorio Capecchi about alleged Italian control of prison. (Prerequisite: Message analyzed; Reward: Burger)
- Investigate Fiona's Desk. (Prerequisite: Vittorio interrogated; Clue: Court Document)
- Examine Court Document. (Result: Court Document)
- Ask Judge Takakura about the old court case. (Prerequisite: Court Document unraveled)
- Move on to a new crime (in Coyote Gorge)! (1 star)
- The case title is an obvious play on the district it takes place in, Sinner's End, and The Scarlet Slayer's life being ended.
- This is one of only seven cases in the game in which all of the suspects make an appearance after the case, the others being At the End of the Rope, A Killer Among Us, In Plain Sight, Sinners and Saints, How the East Was Won and Death in My Hand.
- This is one of the only cases in Mysteries of the Past in which the victim and the killer are relatives.
- This is one of the cases in which the killer has to be interrogated once again during the Additional Investigation.
- In Chapter 1, William Shakespeare is quoted.