Detectives are tracking a missing Toronto high school student's cellphone signal and bank card use to try to pinpoint her whereabouts after she disappeared almost 48 hours ago.

Michelle Yu was last seen Tuesday at about 2:30 p.m. near York Mills Road and Chipstead Road and then at about 6 p.m. when she used her bank card a TD Bank at 354 Bay St., south of Queen Street West, in downtown Toronto.

Investigators have released an image of the 18 year old, who appeared to be alone when surveillance cameras filmed her at the bank.

In an interview with CP24 on Thursday, Det. Const. Roger Marchack said Yu appears to have disappeared on her own free will.

For reasons unknown, she hasn't contacted her friends or family.

Police and Yu's family are concerned for her safety because her disappearance is out of character, she isn't answering her phone and she may not be carrying important medication she requires.

Marchack told CP24's Cam Woolley police are looking into the possibility Yu took a bus out of the city. He urged her to call detectives, her family or her friends to let them know she is OK.

Marchack said Yu's phone has been on and off, and police have left voice messages for her but she hasn't returned their calls.

Meanwhile, Yu's family has been distributing posters featuring her photo to raise awareness about her disappearance.

"We just want to believe that nothing bad has happened to her, she just wants to clear her mind of something and she'll come back to us as soon as she can," Yu's sister Nancy said Wednesday.

Michelle Yu is Asian, five-foot-seven and about 125 pounds with a slim build. She was wearing a grey hoodie, brown moccasins and eyeglasses when she was last seen.

Anyone with information about Yu's whereabouts is asked to call police at 416−808−3300 or Crime Stoppers anonymously at 416−222−TIPS (8477).

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