Corruption of the Body and Soul

For some time, something has been intriguing me and I am sure that you will be able to clarify this for me. I have come to believe that we are all spiritual beings with an occasional human experience. Then it must also be the case that the very basic nature of ‘soul’ is spiritual in nature. We also know that we (‘souls’) have found a place in this material body for our journeys through the time and space. Our body is merely a reflection of our soul and is governed (all its actions) by the very nature of the soul. So my question is that why when the basic nature of soul is spiritual, some ‘bodies’ do the worst things imaginable (the things that are unacceptable in the general society such as violence against other humans etc). Does that imply that those very ‘spiritual’ souls have been corrupted – here I am thinking that the soul is and will always be spiritual. I think that the body (symptom) cannot be corrupted by the source (originator or the soul). I am failing to connect the dots here. Who and What is then corrupting the soul (if in-fact it has been corrupted). Please advise.