Lock 1
In the pocket of the police uniform you find. Just put it on and Lupin will pull it out of the pocket.

Lock 2
Written on a blackboard below the card where you witness Zenigata talking to Teresa (behind two guards).

Lock 3
Two halves of one paper with the code are scattered around before you reach the locked door.

Lock 4
The clues are written in the policeman's diary you find on the floor. The answer is 1355, and it never changes.

Lock 5
The answer is the expiration date on Zenigata's bowl of instant noodles found in a passengers compartment.