The timeline surrounding the disappearance of a Markham, Ont. woman has left more questions than answers after York police said she went missing "without a trace" nearly three weeks ago.

Isabella Dan, 53, was last seen at her home, in the area of Water Walk Drive and Verclaire Gate, on March 3 at around 8:30 p.m.

According to police, she was last seen leaving her home wearing a beige coat with a fur collar and black pants, and was carrying a red gym bag.

“And then suddenly, (she) vanished and disappeared without a trace,” York police Const. Maniva Armstrong told CTV News Toronto Wednesday.

Armstrong said Dan’s sudden disappearance is considered “very unusual,” and her case has been turned over to York police’s Homicide and Missing Persons Unit.

A 2022 grey Land Rover, which investigators believe to be Dan’s vehicle, was left outside of her residence.

Armstrong noted Dan was an avid member at a nearby LA Fitness gym, near Woodbine Avenue and Highway 7, which is roughly three kilometres away from where she was last seen.

CTV News Toronto has learned that Dan scanned her membership card at the LA Fitness on the same day she was last seen, but at 7:46 a.m.

Her gym profile was also scanned five days later on the morning of March 8.

Police have since canvassed several LA Fitness locations in the area in an effort to locate her.

“We have somebody that works in the city of Markham, that has a consistent schedule, contact with people, and [is] known to be a resident in the city of Markham, and then suddenly, vanished,” Armstrong said.

CTV News Toronto travelled to Dan’s law office on Wednesday, but there was no answer at the door and calls to the practice went unanswered.

At this time, police say there’s no information to confirm that this is an abduction, but they are concerned about her whereabouts.

“She hasn’t showed up to her workplace, and it’s really concerning to us, and to her friends, her colleagues, and people that know her,” Armstrong said.

Police describe Dan as being five-foot-seven with a medium build, brown eyes, and black hair.

Anyone with information is asked to contact police or Crime Stoppers anonymously at 1-800-222-TIPS (8477) or online at www.1800222tips.com.