The woman was running past Lost Lagoon at 8:30 a.m. PT when a man came up from behind her and wrestled her to the ground.
The woman fought the suspect off and he fled the area, heading towards Second Beach. Vancouver police and park rangers searched for the suspect but did not find him.
However, Const. Brian Montague says, police found a series of items they believe belong to the suspect including a pair of orange gloves, a black jacket and a Toronto Blue Jay's baseball cap.
"We haven't been able to confirm for certain that these articles of clothing were discarded by the individual responsible for the attack," said Montague.
"We are making that assumption at this point until we can determine otherwise."
Police searching for video evidence
Police describe the suspect as six feet tall, aboriginal and in his late 30s to early 40s.
VPD say this type of sexual assault in Stanley Park is rare. Police hope by releasing a composite sketch of the suspect someone with information will come forward.
"If anyone has any information about who this person may be. If they recognize the composite or if they recognize the clothing at all, give the Vancouver Police sex crimes unit a call," asked Montague.
Police say they are also looking for video from apartments and businesses in the West End to see if they can match the suspect description.
"We'd be looking at areas that lead into the park, the main thoroughfares and the streets, apartment buildings, houses in the area just outside of the park as well to see if we could find video of a potential suspect as well."
The woman was not physically injured in the attack but police say she has been rattled by the incident.
Anyone with any information is urged to call the Vancouver Police Sex Crimes Unit at (604) 717 0602 or to remain anonymous, contact Crime Stoppers at 1 (800) 222 8477 or online at solvecrime.ca.