Mr Roos said he tried to follow the SUV as it turned into Ambler Rd. However, the vehicle sped off and he was unable to find it.
He believed the driver had turned into one of the first driveways on Ambler Rd but he was reluctant to go into the properties looking for the SUV, given what the driver was prepared to do to a dog.
Mr Roos notified the police who, with the SPCA, were yesterday searching for the offender.
Senior Sergeant Swann said Police initially had little information to go on apart from a brief message from the informant.
They had yet to establish whether the dog had been dragged deliberately, tied up and forgotten, or was already dead when dragged.
Bay of Islands SPCA centre manager John Logie urged anyone who had witnessed the incident, or had any information about it, to call (09) 407 7515 urgently. Any information would be kept confidential.
"We're doing everything we possibly can to find the dog and the person responsible for this," Mr Logie said.
In 2005, Joseph Rewha, 52, from Rawhiti, was jailed for nine months - then the toughest sentence ever handed out under the Animal Welfare Act 1999 - after he admitted dragging his dog, known as Tipa, behind his car for about 800m at speeds of up to 80km/h. Rewha was also banned from owning animals for seven years.