2011 Ls Engibe seized question

[CommandoBo]

I was driving home from work the other day and my car died at a stop light and wouldn’t start. After towing it home we changed all the plugs because the codes that posted on the code reader were mostly for cylinder and engine misfires. The oil was low. I didn’t realize the oil was leaking into the engine. We took the plugs out and took the belt off the crankshaft and it won’t turn manually. We drained the oil and used a coffee filer and strainer and didn’t find tiny any big metal shavings. There were a few very tiny pieces but that’s it. I’m wondering what else could cause the crank shaft to seize or if it’s the crankshaft itself, or if I need to consider dropping another engine in it. Any input or suggestion would be appreciated.

[CommandoBo]

Update we found tiny metal shavings on the oil filter.