OP, sorry. Resuscitation can be chaotic and there is a chance that the bag got pushed off to the side and then they missed it cleaning up.
That does not make it okay because it looks like their BVM is in the bag, which means that was placed their after the resuscitation. Your picture doesn’t show anything aside from the little bit of blood that isn’t just garbage, so don’t worry about how to get rid of it, just throw it in the trash. But again, sorry, I’ve never personally and I haven’t worked with anyone who would intentionally leave garbage on a scene after an attempted resuscitation, it’s a small detail that someone’s family shouldn’t have to think about in this kind of situation.