Mid-investigation, Amy and the player disarmed a bomb placed at the scuba diving shop. Later, Roxie told the team that there was going to be a party on one of their crime scenes, the Big Mighty Yacht, prompting the team to hurry the investigation. They then found yacht owner and party organizer Mighty Pete for the murder.
Upon arrest, Pete admitted to courting Valerie for the eye candy, where he kept giving her bigger and bigger gifts as she was playing hard-to-get. Upon racking up enough money, she considered leaving him, humiliating Pete. He then decided to sabotage her scuba equipment with a screwdriver, drowning her upon her next dive. Judge Dante sentenced Mighty Pete to 45 years in prison.
Post-trial, the team discovered that eco-activist Leah Davies was planning to host a gala for the World Coral Foundation aboard the yacht. The player also found a new species of shrimp during a dive with Yann.
- Valerie Green (drowned after her scuba diving equipment was sabotaged)
- Mighty Pete
- The killer uses hand cream.
- The killer knows scuba diving.
- The killer drinks champagne.
- The killer wears a gold chain.
- The killer is male.
- Investigate Underwater Coral. (Clues: Victim's Body, Algae, Scuba Tank; Victim identified: Valerie Green; Murder Weapon registered: Drowning)
- Autopsy Victim's Body. (18:00:00; Attribute: The killer uses hand cream)
- Analyze Scuba Tank. (03:00:00; Attribute: The killer knows scuba diving)
- Examine Algae. (Result: Soggy Paper)
- Examine Soggy Paper. (Result: Party Yacht)
- Investigate Party Yacht. (Prerequisite: Flyer restored; Clues: Torn Photo, Identification Plate)
- Examine Identification Plate. (Result: Identification Number)
- Analyze Identification Number. (06:00:00; New Suspect: Mighty Pete)
- Talk to Mighty Pete about Valerie. (Prerequisite: Identification Number analyzed)
- Examine Torn Photo. (Result: Mysterious Woman on Photo)
- Examine Mysterious Woman. (New Suspect: Angie Cortez)
- Ask Angie about her relationship with Valerie. (Prerequisite: Angie identified on photo)
- Go to Chapter 2. (1 star)
- Investigate Diving Shop. (Available after unlocking Chapter 2; Clues: Handmade Bomb, Valerie's Locker)
- Examine Bomb. (Result: Bomb; New Suspect: Mike Herbert)
- Analyze Bomb. (09:00:00; New Suspect: Leah Davies)
- Talk to Leah about the bomb. (Prerequisite: Bomb analyzed; Profile updated: Leah uses hand cream and knows scuba diving)
- Talk to Mike about Valerie. (Prerequisite: Bomb restored; Profile updated: Mike uses hand cream and knows scuba diving)
- Examine Valerie's Locker. (Result: Clear Liquid)
- Analyze Clear Liquid. (12:00:00; Attribute: The killer drinks champagne; New Crime Scene Unlocked: Deep Coral)
- Investigate Deep Coral. (Prerequisite: Clear Liquid analyzed; Clues: Phone, Broken Camera)
- Analyze Phone. (09:00:00)
- Talk to Angie about her flirtations with Mighty Pete. (Prerequisite: Phone analyzed; Profiles updated: Angie uses hand cream and drinks champagne, Pete drinks champagne)
- Examine Broken Camera. (Result: Underwater Camera; New Suspect: Roger Strout)
- Ask Roger about his photographs with Valerie. (Prerequisite: Camera restored; Profile updated: Roger knows scuba diving)
- Go to Chapter 3. (2 stars)
- Investigate Party Bar. (Available after unlocking Chapter 3; Clues: Faded Paper, Ice Maker)
- Examine Faded Paper. (Result: Letter to the Lawyers)
- Ask Mighty Pete about the letter to his lawyers. (Prerequisite: Letter to the Lawyers restored; Profile updated: Pete uses hand cream and knows scuba diving)
- Examine Locked Ice Maker. (Result: Ice Maker)
- Examine Ice Maker. (Result: Ice Cubes)
- Analyze Ice Cubes. (09:00:00)
- Ask Leah about the Laxatives. (Prerequisite: Ice cubes analyzed; Profile updated: Leah drinks champagne)
- Investigate Shop Counter. (All tasks before must be completed; Clues: Valerie's Bag)
- Listen to what Mike has to say about the victim. (Prerequisite: Shop Counter investigated; Profile updated: Mike drinks champagne)
- Talk to Roger about his anger towards Valerie. (Prerequisite: Mike interrogated; Clues: Victim's Toolbox; Profile updated: Roger drinks champagne)
- Examine Victim's Toolbox. (Prerequisite: Roger interrogated; Result: Screwdriver)
- Analyze Screwdriver. (09:00:00; Attribute: The killer wears a gold chain)
- Examine Valerie's Bag. (Result: Death Threat)
- Examine Threatening Note. (Result: Saliva)
- Analyze Saliva. (15:00:00; Attribute: The killer is male)
- Take care of the killer now!
- Go to Additional Investigation. (No stars)
- See what Angie wants to tell you. (Available after unlocking Additional Investigation)
- Investigate Party Yacht. (Prerequisite: Angie interrogated; Clue: Barrel)
- Examine Barrel. (Result: Toxic Waste Barrel)
- Examine Toxic Waste Barrel. (Result: Unidentified Chemical Product)
- Analyze Unidentified Chemical Product. (06:00:00)
- Ask Leah about the Barrel. (Prerequisite: Unidentified Chemical Product analyzed; Reward: Burger)
- Tell Angie about Leah and the yacht. (Prerequisite: Leah interrogated; Reward: 20,000 Coins)
- Investigate Underwater Coral. (Available after unlocking Additional Investigation; Clue: Fishing Net)
- Examine Fishing Net. (Result: Unknown Shrimp)
- Analyze Unknown Shrimp. (03:00:00)
- See what Roger is up to. (Prerequisite: Unknown Shrimp analyzed; Rewards: Wetsuit, Captain Hat)
- Move on to a new crime! (1 star)
- The title of this case has been inspired by What Lies Beneath, a 2000 American supernatural horror film.
- This is one of the cases of Pacific Bay in which the murder weapon is an action—in this case, the killer sabotaged the victim's equipment to force the victim to drown to death.
- In the crime scene "Deep Coral", you can spot a clownfish and a blue surgeonfish; which are references to Marlin and Dory from Finding Nemo.
- In the crime scene "Party Yacht", the bear (taking aside its color difference) is very similar to Lotso from Toy Story 3.