11/05/2013 04:11 EST | Updated 01/23/2014 06:58 EST

Police release composite sketch of man believed to be behind UBC sex assaults

VANCOUVER - The recollections of six women who were attacked while they walked alone at the University of British Columbia have helped Mounties produce a composite sketch of the man believed to be behind the fear that has swept the campus.

The sketch, released Tuesday, shows a slightly unshaven man wearing a hooded sweater. He is described as being Caucasian, with an olive or darker skin tone, a rounder chin, broad forehead, straight nose and short dark hair.

The man is also described as having a tall, thin build, and is believed to be in his mid-20s to 30s.

RCMP spokesman Sgt. Peter Thiessen told a news conference the composite sketch was based on statements by the six victims. He also said investigators with the major crimes section have received more than 20 tips related to the series of attacks that began in April, with three women being assaulted in separate incidents last month alone.

But Thiessen said while RCMP have compiled a list of persons of interest, they have yet to identify the suspect.

"We are doing everything we possibly can, we are utilizing...every tool in our toolbox to identify this individual," he said. "We're as frustrated as anybody else that this individual has not been identified."

RCMP has bike patrols, a dog squad, and teams specializing in behavioural science, criminal and geographic profiles, and crime analysis on the investigation.

The six women were all attacked as they walked alone late at night on campus. Three of the attacks occurred in October, with the most recent one happening just over a week ago. One incident was reported in late September and investigators announced last month that separate incidents in April and May are also connected.

The sexual assaults have led to heightened security measures at UBC, including increased campus patrols and extended hours for the free Safewalk program that allows students to be walked home with two people late at night. A new program called Rezwalk has also been introduced.

The university said copies of the composite sketch will be distributed across the campus, including student residences. They will also be sent via mass email and be posted on its Stay Safe website, said Louise Cowin, vice-president of students.

"This is an important development," she said in a written statement. "These attacks have become our top priority and we hope this RCMP drawing will lead to a break in the case. We are asking all members of our community to provide any information they can to help the RCMP find the perpetrator."