Grand Theft Auto III/The Thieves

Brief
Marty hired some thieves to loot his house so he could claim on the insurance. But now they're threatening to tell the insurance company the truth if he doesn't give them a bigger cut. And so it's time for another friendly "talk".

Walkthrough
Take the Sentinel and go pick the thieves up. After the "talk" take the car to the Pay and Spray, then return it to the factory.

NOTE: if you want to temporarily keep a locked Sentinel that no-one can jack you out of, run away when you exit the car so Claude doesn't shut the door. Then get back in. Now you can do whatever and no-one can drag you out because the doors lock as soon as the mission is complete. However if you stow the car the doors will unlock, and if Claude shuts the door when you get out you won't be able to get back in.