It seems to be getting common now for people to steal catalitic converters as they are stainless steel. They take them to recyclers to get money for them.
I have put straight through pipes on mine and removed the cats, but it still runs. Maybe they have done something under the car that is causing it not to start. Have a look around underneath and see what you can find. Hope they did not destroy too much.
These thieves have done a lot of damage to a lot of cars locally here !
it can. when converter got stolen the o2 sensor probably went with it. without that 02 sensor your computer wont know how much fuel to put into the engine to let it turn over. ever heard the term running lean? means not getting enough fuel (can cause alot of damage if your running lean)