ATLANTA -- Several animal rescue groups have pitched in and the reward for information leading to the arrest and conviction of a puppy killer has increased.

Southern Cross German Shepherd Rescue together with the Primate Freedom Project told Channel 2 they were offering $3,000 to anyone who led authorities to a person who stabbed and mutilated a German Shepherd and left it along Pleasant Hill Road in Gwinnett County in November.

Monday, officials with the Atlanta Humane Society said they are also offering a $2,500 reward for the arrest and conviction of the person responsible.

Investigators said the person who killed and dismembered a puppy and left him behind a store is cruel and violent.

Police said an employee at a shopping center on Pleasant Hill Road found a dismembered German Shepherd puppy behind a store. After a necropsy, investigators determined the puppy had been stabbed before or after he was dismembered.

"To know that he was in the pain he was in before he died is incomprehensible to me," said Molly Moncure with the Southern Cross German Shepherd Rescue.

The sadness and outrage have led to a combined $5,500 reward for information leading to the arrest and conviction of the puppy's killer.

"I'm absolutely positive that someone knows who did this. I'm hoping the reward money will bring that person forward with tips so that the person can be caught, apprehended, and convicted," said Moncure.

If you have any information on who is responsible for the crime, you are asked to call Gwinnett County authorities at 770.339.3200.

If convicted, the person responsible for the crime will get at least a year in jail and/or a fine of up to $15,000.