I had a laser attack flying into Leeds at night in a corporate jet I had an FO with me.
It was temporally blinding, startling and we reported it to ATC but not IMO incapacitating.
Where I feel it could be incapacitating is if you had an unknown tendency to fits or other intense light induced conditions where such an attack could bring on that condition.
To find the culprit would be like finding a needle in a haystack
Pace