They could, but what does that have to do with the situation? Psychopathy affects approximately 1.2% or the population, so given that autism affects 2.2% of the population, the combination would have a prevalence in 0.027% of people
I think that's a number so low, that it's not worth discussing, given that a psychopath with full mental capacity would undoubtedly be more dangerous
I'm not sure that you can just multiply those probabilities (are they both uncorrelated? Can autistic people even become psychopathic?), but,
0.027% * 300 million people in the US = 81,000 hypothetical autistic psychopaths, which is over 1600 per state. That's plenty to worry about from an administrative (e.g. police) standpoint.
I think that's a number so low, that it's not worth discussing, given that a psychopath with full mental capacity would undoubtedly be more dangerous