I'll be walking you through the 'Nicholson Electroplating' Arson Case. While it's a guide for this achievement, I've also included all the achievements for this piece of DLC!
This case takes place before the finale, right after the 'Polite Invitation' case. I've tried to ruin very little of the plot, but there are still going to be a couple spoiler-ish details. So, yeah, you've been warned.
When the case starts, you have to drive to the explosion that rocks L.A. After getting there, you're tasked with subduing some looters. Then, it's on to investigating the explosion.
First, examine the fabric to the far left of where the mayor is giving his televised interview.
Clue 1) Laundry tag
Beyond there is a suitcase in a burnt-out locker. Inside are a couple things. First, examine the silver rectangular device.
Clue 2) Spy camera
Clue 3) Espionage
Then, check out the small gold bauble. After pocketing it, read the business card. And finally, examine the cypher. To decipher the message, you need to line up the 'H' on the outer ring to the 'K' on the inner one. From there, move the outer ring to read the circled address in the paper.
Clue 4) Deciphered message
Next, move to the back of the explosion site. There, you'll find an officer examining an odd metal ring. Upon further investigation, you'll slide the two pieces together to get a label and realize it's a part of an airplane.
Clue 5) Airplane part
[Achievement: The Nose Knows]
Find and inspect the prop spinner at the Nicholson blast site.
Move to your car. On the way, you'll meet the owner and interrogate him.
- Nicholson plant explosion - Doubt
- Whereabouts of Okamoto - Lie (Spy camera)
- Whereabout of McLellan - Doubt
Before leaving or letting your partner drive, drive to the corner of Beverly Blvd. and Hobart Ave. nearby and use the police phone to get the address for Superior Laundry Services. Head there.
Superior Laundry Services
Speaking to the man in-charge, he'll let you take a look in the log and find the owner of the blown-up shirt yourself. Tag number is 'J2620'. Use the telephone on the way out to try and find an address for the owner, which is a no-go. Next, head to the 'Deciphered Address'.
Before, heading in, check out the mailbox to discover where you actually are.
Upon arriving in the apartment, start by checking out the refridgerator, then examining the body that falls out. Start with his head. Then his left arm, where the wristwatch is a point of interest.
Clue 6) Wristwatch
On his right hand is another clue.
Clue 7) Ring
Check the fireplace next for a gold trinket.
Clue 8) Tie pin
Head into his bedroom and check next to the sink to find the partner to the gold bauble you found earlier.
Clue 9) Microfilm
[Achievement: Skeletons in the Icebox]
Find and inspect all clues inside Okamoto's ransacked apartment.
Head back into the main room and use the telephone to check your messages. You'll get the address where that airplane part came from and also what it is. Head there next.
When you arrive, the Military Police will hold you at the gate. But, Biggs' acquaintance Vernon Mapes will escort you in. Follow him to the hanger where you'll interrogate him before having a look around.
- Nicholson plant explosion - Doubt
- Knowledge of Okamoto - Doubt
- Knowledge of McLellan - Lie (Prop spinner)
Start by going into the upstairs office directly behind you. In the back will be two photographs. The one on the right will yield a hint of an address. The one on the left is a clue.
Clue 10) Photograph
The next point of interest is under the nose of the plane. There, you'll find some large metal drums of Alcott's Linseed Oil.
Clue 11) Linseed oil
Inside the plane itself, you'll find a ladder that'll take you up into a makeshift office. Examine the bulletin board nearby to find a note bearing latitude and longitude.
Clue 12) Navigation note
Next, use the navigation machine in the room to discover what is located at those directions. You're looking for "24 15' north, 76 00' west".
Clue 13) Bahamas
The final point of interest is outside, to the back of the plane. There'll be workers buzzing around three Pratt & Whitney 4360 aircraft engines. Approach them and Cole will ask to take a look.
Time to return to the station.
Wilshire Police Station
After speaking to the always-friendly front desk officer, you'll find out you're wanted downstairs in Technical Services. Head there, and you'll be tasked with examining the photographs from the camera you found earlier. The first photo is the one Phelps accidentally took of himself earlier. Nothing of interest.
Examine the wristwatch on the gentleman in the second photo to discovers it is the man we found in the fridge earlier.
The third photo shows Mapes with Howard Hughes. Mapes' tie-pin looks familiar...
The fourth photo shows the formula for the aluminum bath McLellan was working on and the fifth photo shows what may be Harold McLellan.
The sixth and final photo reveals the house number on the door to go along with the partial address we had from Hughes' photographs in his office.
After leaving the magnifying glass, Pinker will ask you to assist in his experiment. The order you want to add the ingredients in is: linseed oil, acetic anhydride, perchloric acid. BOOM!
Finally, before leaving, there's a final piece of information behind the central counter where the photos are.
Clue 14) Aluminium polishing patent
Anyway, time to head to the house in the photograph.
House in Photograph
You'll find the door open when you arrive. Phelps and Briggs will get jumpy and draw their guns, but when you go inside you'll find it empty. Head to the stand over near the bed to find a passport and a TWA ticket. After examining the passport and putting two-and-two together, someone'll try and silence you both by setting the house on fire. To escape, you'll need to shot the gas can near the stove to blow a hole in the wall. Run to the adjacent room and in the back will be a window you can climb out of. Outside, you'll find it was Mapes who tried to kill you. He'll jump in his car and it's time for a car chase. Don't worry about stopping him, just tail him. But be careful: during the chase, some of his security friends will join the chase and try to take you off the road. The chase will end at Hughes Aircraft. If you were able to successfully tail him in one attempt...
[Achievement: Out Of The Frying Pan]
Pursue Vernon Mapes from the burning house to Hughes Aircraft on your first attempt.
Upon arriving, you'll be assaulted by the military police. During the onslaught, four cars (three in-front of you, one behind) will join the fight. If you can shoot two of the drivers before they get out...
[Achievement: Bulletproof Windshield]
Kill the drivers of two of the MP vehicles in the Hughes Aircraft gun battle before they pull up.
After taking them all out, head into the hanger after Mapes where you'll run into more MPs and Mapes on a machine gun. And that wraps it up!
[Achievement: The Big Unfriendly]
Complete 'Nicholson Electroplating'.