Police and dozens of volunteers spent much of the day searching for a missing York University doctoral student who was last seen in Toronto on Thursday morning.

Police said Zabia Afzal, a 30-year-old resident of Vaughan, was spotted in the area of Highway 400 and Major Mackenzie Drive West at around 9:40 a.m. on Thursday and was last seen in the area of Ashbridges Bay in Toronto about an hour later.

Investigators say police and family members are concerned about her well-being.

The York Regional Police helicopter has been assisting in the search, as well as Toronto police, who are conducting ground and water searches.

Family and friends have also organized searches for Afzal, including one at the Scarborough Bluffs today.

Afzal's brother Zubair told CP24 Sunday that volunteers would also be looking for the missing woman in the Thorncliffe Park area and on the Toronto Islands.

So far, he said about 70 people have volunteered to help find his sister and community members have placed about 7,000 posters across the city.

"We felt as a family and friends as well that perhaps we could do a little bit more to help out," Afzal's brother said.

He added that his sister has been a strong advocate for women's rights and is currently in a PhD program in public health at York University.

"She is a very loving and caring individual," he said. "We are absolutely worried about her safety."

Afzal is described as five-foot-four, about 128 pounds, and has shoulder-length, dark-brown hair.

She was last seen wearing black pants, a black or navy zippered hooded sweatshirt, and a green floral shirt.

A spokesperson for York University said the school has been doing what it can to pass the message along to the rest of the university community.

“We have been sharing updates with York community members and encouraging anyone who has information to connect directly with the police or our community safety team immediately,” York spokesperson Barbara Joy said in a statement. “We have posted a message to our Community Safety website, updated our Safety App with details and important contact information, and we have connected with the police.

“We will continue to update our community and share the #FindZabia updates through our social channels and urge everyone to do the same. We hope that Zabia is somewhere safe, and found quickly.” 

 Anyone with information on her whereabouts is asked to contact York Regional Police or Crime Stoppers anonymously.