Investigators say a vehicle that struck and killed a woman and a dog in Central Saanich Monday night may have been involved in another collision just 20 minutes earlier.

Police are looking for witnesses of the second incident, which happened at Mount Newton Cross Road and Lochside Drive around 6:45 p.m. Monday.

They say new information described a black sedan that was rear-ended by a red Jeep.

Police now want to speak with the driver and any occupants of the black sedan or anyone who has information on Mount Newton Cross Road collision.

About 20 minutes later, a vehicle described as a newer Jeep plowed into two women walking on the shoulder of the 7600-block of Central Saanich Road.

A 51-year-old woman and a dog were killed at the scene while the woman's sister was rushed to hospital in critical condition.

The 26-year-old man driving the vehicle, identified by family as Tony Thomas Jr., was briefly treated for minor injuries and is cooperating with police.

Investigators are still looking into the cause of the fatal crash and say the driver's sobriety is a key consideration.

Those with information on that crash or the collision at Mount Newton Cross Road at Lochside Drive are asked to call police 250-652-4441 or make an anonymous call to Crime Stoppers at 1-800-222-8477.