You don't need any expertise to determine if the steel ripped apart or was cut IMO.
How can you possibly say that you don't need any expertise to determine what caused the break? The difference may in fact be impossible to tell to the untrained eye.
It's like someone at LC once said: "Would you consider that a clean cut on a sheet of paper indicates the usage of scissors? Because I do."
Someone pointed out to him that a scalpel would do exactly the same thing.
A regardless of this, your hypothesis doesn't take into account that it may have been cut during the process of cleaning up debris.
I, however, will await the professional judgement of someone with the knowledge required to explain this.
You may disagree but you cannot justifiably deny the possibility that they were cut.
I cannot, no. Others may be able to though. And just because there is the remotest possibility that your claim may be true, that doesn't mean that it is true, or even that it is probably true.
It's possible that my neighbour comes into my room while I sleep and removes some socks, explaining why I have odd socks left over at the moment. However, it is a remote possibility, and the preponderance of odd sock can more probably be explained by the fact that my room needs a clean at the moment (just moved a lot of stuff in).
I can set up a test for this, and that would provide me with evidence to make a judgement one way or the other. But until (or if) I decide to do that, I will have to accept that while it is possible that my neighbour is sneaking into my room, it is probable that my room is just too messy to find anything right now.
See the analogy?