Police and marine units continue to search for a York University doctoral student who went missing last Thursday near Ashbridges Bay in Toronto.

Police said that Zabia Afzal, a 30-year-old resident of Vaughan, was last spotted in the area of Highway 400 and Major Mackenzie Drive West around 9:40 a.m. on Thursday. Her family said she took an Uber to Woodbine Beach and arrived about an hour later.

Afzal’s cell phone and shoes were both found on the beach. She is being described as five-foot-four, about 128 pounds, and has shoulder-length, dark-brown hair.

On Sunday, dozens of volunteers helped police search the areas of Ashbridges Bay, the Toronto Islands, Scarborough Bluffs, and Thorncliffe Park.

Afzal’s brother, Zubair, said that volunteers helped plaster the city with about 7,000 posters.

"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 on Sunday.

Monday morning, Toronto police sent divers into the water near the area.

Zubair doesn’t think the details of the investigation add up and is hoping that more volunteers will join their search Monday evening.

“I saw her on Thursday morning at breakfast,” he told CP24. “We had a proper conversation like a normal day. It doesn’t make sense whatsoever.”

“We are worried for her health and safety,” he said.

Afzal is enrolled in a PhD program in public health at York University and was a strong community advocate for women’s rights, her brother said.

A spokesperson for York University sent out a message over the weekend to the community, saying they were sharing updates with students and staff and are encouraging anyone with information to contact the police.

“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,” York spokesperson Barbara Joy said in a statement.

“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.”