Is this protocol?

I help take care of intellectually disabled adults. Weekends Friday-Sunday

I guess they found bruises on a resident i help in the home. I helped him Thursday night and got him up for the day on Friday and they reported the bruises today. I didn't help him Friday night or Sunday at all, but my supervisor asked me what he thinks what may have caused them. And I said I didn't know or noticed the bruises and I didn't. I didn't do anything. I am worried I am gonna get blamed for this? Or is this protocol to ask everyone what happened?
Is this protocol?
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