No, a horrible angry man committed those murders. 

And anger is not a psychiatric illness, and it does not preclude one from purchasing a gun in the USA.  And the reason he killed 26 and injured many more is because of the zany laws in the US which allows for massive clips, and assault rifles to be used.

And what led to this: a foolish interpretation of the second amendment.

My condolences go out to these families, too. But I would like to see the US change the laws so this doesn't happen again, rather than just sending out condolences and waiting for the next tragedy.