DLC: "Reefer Madness" Case - L.A. Noire

Mike Lymon's Bar

Talk to Freddie in the back

Juan Garcia Cruz's Residence

As you come up to the house, Juan, and an accomplice will shoot at you, so take them out! (To get the "Forcible Rear Entry" achievement, shimmy your way to the left of the wooden fence, run to the back, jump the fence and go through the door and kill your enemies.)

Juan Garcia Cruz's Residence (Crime Scene)

After the shootout, search Juan's body to find his silver dollar in the right pocket, and his wallet in the left.

As you get up from the body, turn to your left to find a note reading; "Masangkay"

Turn right from the note  and look at the soup boxes on the right side of the doorway.

From there, go to the back room and look at the newspaper flyer.(If you head straight to the 20th century market after you pick this up,  you will get the "High Flyer" achievement, but you will most likely get only three-four stars.) 

Juan's Stash Room

After that, go out to the shed in the back yard, go to the shelf with four cans, and pick the can that says "Flour" on it.

Go into the secret room and pick up the cans next to the can opener and open them both to find clues, and also you will get the achievement "Soup In The Pot" if you choose to do so.

Go to the ledger on the table and tap the initials E.J.

Parnell's Soup Factory

Talk to the woman to see Mr. Parnell.

In the Ledger, tap on Jorge Garcia Cruz's name.

Interview with Mr. Parnell

Factory sealed soup cans-Doubt

Parnell's soup company-Doubt

Knowledge of Cruz Brothers-Doubt

Inside man Jorge Garcia-Truth

Parnell will now take you to Sergio.

Look in the ledger and tap on "20th Century Market"

Interview with Sergio Rojas

Factory sealed soup cans-Doubt

20th Century Market-Lie, Evidence: Juan's silver dollar

20th Century Market

Chase Airto Sanchez.

Interview with Airto Sanchez

Knowledge of 'E.J'-Lie, Evidence: Juan's silver dollar

Parnell's soup shipments-Doubt

Juan and Jorge Cruz-Truth

Parnell's Soup Factory

Kill everyone in the shootout.

Search Ernesto's body to find; his wallet in his shirt pocket, and the silver dollar in his left hand.

Look in the box next to Roy.

Search Jorge's body to find; A money roll, and his silver dollar in his shirt pocket.

Coin Puzzle

Make out the coins to Spell: MAS ANG KAY MET ALS.
(You will automatically obtain the "Spare A Dime" achievement after you make out the puzzle.)

Masangkay Metals

Go to the left parking lot, and jump the cement wall with no barbed wire.

Head to the back of the building, Kill everyone on the ground, middle, and top floors.

If you follow Roy you'll see where to go.

After it's all done, you'll get the "Every Herb Bearing Seed" achievement as a reward.