An investigation into a spate of dog deaths has concluded the most likely cause was rat poison put down by a resident.
North East Lincolnshire Council said no suspicious substances were found at Cleethorpes Country Park after four dogs died after being walked there.
Tests suggest two died as a result of rat poisoning, one of natural causes and the fourth death remains a mystery.
Officials said the substance was probably put down by a local resident.
They said no rodenticide or any other contaminants were found in the sweep of the area and the authority does not use the substance in the country park.
Andrew De Freitas, the leader of North East Lincolnshire Council, said: "We are now able to say with confidence no substances of a suspicious nature have been found on Cleethorpes Country Park since the investigation was launched earlier this week.
"While nothing has been found to link the deaths to the park itself, we would urge pet owners to remain cautious for the time being and try to keep an eye on their pets.
"As an authority we would also like to remind the public that rodenticides should only be administered by professional organisations and not by householders."
Symptoms of animal poisoning by vitamin D-based rat poisons include depression, lack of appetite, an increase in drinking and urinating, vomiting and diarrhoea.