By The Book GTA 5 (Walkthrough)

The mission is now starting, By The Book.

Switch to Trevor and go to the warehouse.

Trevor and Michael will meet the agents.

Get in a car and drive to the house.

After reaching there, Dave will call Steve to tell him that it's the wrong house.

Pick any tool to torture K, to find the right information.

After you torture him, he will give the information.

Get in a car, and drive to Chumash.

Trevor will torture him again to get more information about the guy.

You have to find the target, using the sniper rifle's scope.

Pick another weapon to torture him, to find more about the target.

Pick up the wrench and swing it on his knee.

K will tell you that the target got a bushy beard.

Zoom in the scope and find guys with beards.

You can torture him by giving him electric shocks.

Mr. K will tell the target chainsmokers Redwood and he is left-handed.

After you find the target, shoot him.

Get in a truck and take Mr. K to the airport.

The mission is now complete.