York Regional Police are investigating after a dog that ate a contaminated substance near a Woodbridge mailbox became so ill that it had to be euthanized.

Police say the dog and its owner went for a walk in the Shawbridge Boulevard and Gidleigh Park Crescent area on Nov. 25. While on the walk, the dog ate something near a mailbox. Later in the day, the canine became violently ill and by the next morning, it was so weak that it couldn’t walk.

The owner took the pet to the veterinarian, who said the symptoms were consistent with anti-freeze poisoning.

The dog’s condition eventually deteriorated to the point that it had to be put down.

On Monday, the owner called police after finding dog kibble spread around a 15-foot area surrounding a mailbox in the same area.

In a news release, police said they have taken the kibble for analysis to determine if it is laced with glycol (antifreeze).

Police are asking anyone who noticed suspicious activity in the area to come forward. Dog owners and parents are also being advised to use extra caution to make sure that pets and children don’t eat anything that is found on the ground.

The suspicious incident comes the same day police in Toronto’s Thorncliffe Park neighbourhood issued a similar warning after a dog became ill from eating treats found while out on a walk in that area on Nov. 27. Police have not provided any indication that the two incidents are linked, however.