Animal welfare inspector Anna Porteous was shocked by the nature of the incident.
"People sometimes leave dogs, that's not unusual, but to actually throw her off a bridge and into water - that's just low. It's not even giving the dog a chance," she told the Bay of Plenty Times.
I too find it hard to understand how someone could be so callous.
The only bright note to come out of the case is the willingness of prospective pet owners to take Charity into their home.
As reported on page 12 today, the SPCA has received numerous adoption offers but the animal welfare agency has decided to put her into foster care until she becomes less timid and more trusting of humans.
Given her recent treatment, that could take some time but there is hope that the dog will find a loving home.
As well as proving care, the SPCA deserves credit for continuing its search for the culprit - hopefully they will be successful and the person responsible held to account.