When I engage the clutch, the engine dies. The baldes turn freely, so it looks like and electrical problem. Is there a safety device that would kill the engine when the clutch is engaged?

All modern riding mowers now days have several safety switches and or relays/micro switches. Some are simple blade switches that make or break contact depending on the position of a lever. There is a contactor under the seat that will kill the engine if you fall off(you have to sit on it for it for the engine to keep running). There is one that kills the engine if you put the mower in reverse with the blades engaged. And there is a contactor that senses wether the mower blades are in fact engaged or not. It may be awkward but you can look at all the mechanisms and find where the different contactors are and move the levers back and forth to see if they aren't dirty, bent, or a securement screw is loose or missing. It is also possible that one of the wires are broken or have come off of its connection point. Once you inspect them you should be able to determine the next course of action. These are not hard to fix although they can be difficult to get to. If it has a micro-switch at one of these locations you may need to test it with a continuity meter to determine if it is good or not.