'96 Landcruiser Ignition Problem

[Zog]

I've had my '96 Landcruiser since it was new and put 85K completely trouble-free miles on it. It is stock except for a TRD supercharger I installed about 30K miles ago. I recently gave it to my sister (who has terrible luck with cars) and she has put an additional 10K miles and has started to have an intermittent problem.

Several times after she starts it, the starter continues to run. It doesn't grind, you can just hear it spinning. After a few seconds almost every warning light on the dash lights up (I haven't seen it so I don't know exactly which ones). She can then turn off the key and even remove it completely and the engine continues to run and the starter continues to spin. She can usually get the engine to stop by inserting the key and turning it to start a few times and then to off.

She can reproduce the problem exactly if she just turns the key to start and then continues to hold it there -- the starter runs and then all the warning lights come on but when she is simulating the problem, the motor stops if she then turns the key to stop.
It sounds like a bad ignition switch to me -- but the mechanic at the Toyota dealer swears he tested the switch and it is good. He also said there are two relays that would both need to be sticking for the engine to run with the key off so doesn't think it is a relay issue. The starter was tested and no problems found -- plus I don't think that would result in the warning lights if it was a solenoid plsu I believe it would not continue to run unless the ignition switch was telling it to.

I'm just about ready to tell them to replace the ignition switch anyway but was hoping someone here might have seen this exact issue or have any other ideas. Since it is an intermittent problem it seems to me the switch could test good at the time since the problem wasn't occurring either. The Toyota mechanic actually thought it was the alarm (factory) at one point and removed it for two weeks while my sister drove it but the problem reoccurred.

Thanks!