Is the piston still loose in the bore? What's the ringgap?
Any damage marks on the cylinder wall from a possible piston seize?

I've once seen an engine where the camshaft had broken in half, piston ringlands were cracked and the rod was broken with some crank/bearing damage.

The shop who put the engine together thought they had gotten a badly cast cam and tried to go after the cam company.

What they didn't (want to) see was that they had built the engine with too little ringgap clearence, which caused that particular piston start to seize up high in the bore, causing excess stress on the bearing for a while and finally snapping off the rod and bolts as the remains got pulled down by the crank, and while that happened, the still rotating cam was trying to open the valves, which broke because the valves were blocked by the stuck piston.