York Regional police are looking for witnesses after a 28-year-old woman and her dog were killed when they were struck by a vehicle in Vaughan.

The pair was struck by a northbound Lexus sedan that jumped a curb on Thornhill Woods Drive, near Summeridge Drive, on Monday at about 8:15 p.m.

Biana Cherniavski was pronounced dead at the scene. Her two-year-old dog Harley also died.

In a news release, police said they do not know what caused the Lexus to cross the road, mount the curb and then travel along a sidewalk, where it struck the Vaughan woman and her dog.

After striking the woman and the dog, the Lexus struck several trees and flipped onto its roof.

The 84-year-old woman who was driving the Lexus and her passenger, an 88-year-old man, were taken to hospital, where they were treated for non-life-threatening injuries.

Police continue to investigate the crash.

No one has been charged.

Anyone with information is asked to call police at 1-866-876-5423 ext. 7704 or Crime Stoppers anonymously at 1-800-222-TIPS (8477).