Almost every Mastermind's name has letter 'a' on it, so when you're
going to arrest the first suspect, type 'a' on the computer search and
you'll see Masterminds name, city and organization. In the Mastermind's
place, type Mastermind's full name in computer and you'll get enough
evidence to arrest. Mastermind will then give you all important info
from other agents involved, so you can just travel around and pick them
If you can't find enough letters to solve the computer password, don't
panic. There is limited amount of passwords and the passwords is changed every time you try to guess one, so if you keep on trying
with some short ones like 'large' or 'drugs', you'll hit the right one.
The most important part of the game is combat. Everything you need
to know can be found from the houses and some important things
can only be found from there. So train combat to maximum when you
start. Essential combat equipment includes Uzi, armor, motion director
and safe cracking kit (always open every red safe!) Don't bother for grenades, you'll get them from bad guys. Remenber to walk near the
walls, especially at higher difficult levels, because enemies will throw
grenades through open doors (you can too!).
When you have turned somebody to double agent and arrest her again,
she will not stay as a double agent unless you get new information how
to turn her.
You get more points if you arrest some agents (kidnappers, paymasters, thiefs etc) after they have done their work so you can free the hostage/pick up the money. Remember not to wait bombers though.
If you're being chased with a car, don't bother trying to escape. Just
stop and fight, since there are often only one bad guy.