Pet Owner's Responsibility?

In the case study about the dog mauling in San Francisco, much of the question regarding charges and how to deal with the death of the victim was who should take responsibility? When a pet is aggressive and attacks someone, is it the owner's fault if that victim gets severely (or even fatally) wounded? In this case the owners of the dogs, Marjorie Knoller and Robert Noel, were found accountable for what their dogs did to Dianne Whipple, the victim of the tragic mauling. Knoller and Noel were not initially going to be charged with anything, but with public outrage growing due to the backfiring of the couple's callous public statements, Knoller was eventually charged with the second degree murder of Whipple; both she and Noel were charged with manslaughter and the knowing possession of a mischievous and dangerous animal.  In the first trial, the couple were found guilty on all counts, but the second degree murder charge for Knoller was overturned by a judge. However this overruling was appealed by the state of California which resulted in the reinstatement of this charge. The public, not only locally but worldwide, was very vocal in their opinions on the case. This heavy public voice could be one reason all of the responsibility for the attack was placed on the owners. What do you think? Was the ruling reasonable, or should less responsibility be placed on Knoller and Noel for what their dogs did to Whipple?