Grand Prix Rejects

It seems the only site about his death so far(other than Wikipedia)is in Italian

Colombo won the 1974 Italian Formula 3 championship, and in 1978 unsuccessfully twice attempted to qualify an ATS and failed to even prequalify the awful Merzario offering.

He had a profile on t'old site, which Wikipedia still links to (as is the case with quite a few other drivers who would have been forgotten if it hadn't been for the efforts of two Australians two decades ago).

I think he was a better driver than his stats suggest.