Saab intermittent start

I drive a 2000 Saab 9-5 wagon. Every couple of weeks it won’t start after a short drive. All other electrical systems work, but the care won’t crank. If I keep trying, it might start after 10-15 trys. If I just let it sit for awhile it will start. The Saab dealer tried to find the problem for 10 days and over 75 miles of driving, no luck. Other people on a Saab owner’s website have the exact problem. Some feel it is tied to the security system. HELP!!.