TORONTO -- Police are looking for witnesses who may have seen a 16-year-old girl at a house party in Brampton prior to the moment she was fatally struck by a car over the weekend.

Dianna Manan was found by a passing motorist lying in the eastbound lanes of Queen Street, near Cherrycrest Drive, shortly after midnight on Jan. 5.

Emergency crews transported the teenager to a trauma centre with life-threatening injuries, but she was later pronounced dead.

The vehicle involved in the crash did not remain at the scene.

Her family said that Manan was picked up by friends from her grandmother’s home in Toronto around 10 a.m. the day before her death.

Her mother told CTV News Toronto that she didn’t know way her daughter was in Brampton.

"She never mentioned Brampton," Savi Lakeram said. "I know somebody out there knows something about her."

On Tuesday, investigators said that Manan had “loose affiliations to Brampton” and may have spent some time at a house party on Saturday night prior to her death.

“Investigators from the Major Collision Bureau are requesting that anyone who was at the party and remembers seeing Dianna to contact them,” police said. “It is also believed that Dianna may have left the party with someone.”

Manan has been described as standing at about five feet, with brown skin and a slim build. She was last seen wearing a black three-quarter length winter jacket with fur around the hood.

Investigators have also said they are interested in speaking with a young male who was at the collision scene and provided information to another witness. He has been described by police as South Asian with a slim build, in his late teens or early 20s.

Manan was a Grade 11 student at Aurora High School before moving to Toronto to live with her grandmother in September. Her mother described her as a “happy kid” who wanted to become a paediatrician.

Anyone with information is being urged to contact police or reach out to Crime Stoppers anonymously.