Police now say they believe a TTC vehicle struck and killed a woman who for reasons unknown laid down in the middle of a roadway in west Toronto early Tuesday morning.

Emergency crews were called to Lansdowne Avenue, south of Dupont Street at 1:30 a.m. for what was initially reported to them as a pedestrian struck.

They arrived to find a woman in her 40s in the middle of the road, suffering from multiple traumatic injuries.

She was pronounced dead at the scene.

Investigators said a woman was seen by witnesses crossing the street prior to the collision.

She laid down in the centre of the roadway.

Later a TTC maintenance vehicle was passing through Lansdowne and spotted a garbage bag in the street.

The woman was still in the roadway and attempted to roll out of the vehicle's path but was struck.

The TTC driver circled back after the collison and discovered the unconscious woman on the roadway.

She is not being identified pending notification of next of kin.

Lansdowne Avenue was closed between Dupont Street and Lappin Avenue until the morning rush hour to allow for an investigation.

Anyone with video of this area at the time of the collision is asked to call Toronto police traffic services.