DEARBORN HEIGHTS, Mich. -

There's a mystery surrounding who tied a rock to a dog and threw it into the Rouge River in Dearborn Heights.

A driver noticed the animal on Aug. 26 near the intersection of Warren Road and Outer Drive.  

Officers responding to the call and recovered the dog from the muddy bank of the river.

The dog was covered in mud, but appeared to be in good condition.  Officers took him to the Dearborn Animal Shelter.

After several days in the care of the shelter, the dog has made a full recovery. 

Workers at the shelter have named the pet "River."  They say he is doing well and has a healthy appetite.  

The focus now shifts to finding River a home and finding the person responsible for this. 

"Animal cruelty of any kind is deplorable, but this situation seemed vicious in its intent.," said Elaine Greene, executive director at Friends For the Dearborn Animal Shelter. "The dog, a handsome labrador/retriever/hound mix appears to be very friendly and we are disturbed that anyone would do such a thing to him."

River will soon be ready for a new home and available for adoption from the shelter.

The Dearborn Animal Shelter is offering a $1,000 reward for information that leads to an arrest.

Call the Dearborn Heights Police if you have any tips at 313-277-7408.