But then you'd also have to find out how many people who they accepted and went to other schools ended up committing such crimes, which would be impossible. For example we know this guy matriculated at BU, but for all we know was accepted at multiple med schools, all of which accepted an alleged murderer. The med school you guys are applying to may have accepted him, and may accept someone similar into your own first year class -- watch your back. Food for thought.
I don't think BU did anything wrong. However I do think some of their application practices deviate from many other schools and it may contribute to the fact that they really didn't seem to get as much insight into the minds of at least two of their matriculants as other schools which have been around longer and never had similar experiences. There's perhaps something to be said for more essays and putting great weight on some of the non-numeric factors.
This also perhaps is a good lesson for schools on how much safer it is to admit nontrads, since they have more years of life to evaluate them on -- if someone is going to snap, they tend to do it in their younger days -- with the 30 year old career changer you pretty much know what you are getting.
The younger applicant (as this guy was), not nearly as much.