Halifax police have released new details about their investigation into a string of alleged sexual assaults by cab drivers that have unnerved local women, confirming there have been a dozen remarkably similar cases in the past four years.

Of the 12 cases, five were reported to police in the past three months alone, prompting a heated debate over taxi safety.

"We've had a recent rash of these events, and people have been inquiring about these assaults and what they can do for their own personal safety," Insp. Lindsay Hernden said Monday in an interview.

"We also want the victims to understand that this is not their fault. They were victimized by perpetrators seemingly operating with the same (methods) ... We've got a series of things in these files that stand out."

Charges have been laid in five cases, but three cases have been closed due to lack of what police call "solvability." Of the remaining four cases, three are still under investigation and one was closed at the request of the victim.

He said the details indicate a pattern of events that "paint a pretty vivid picture of how these offences are playing out."

In each case, police say the suspects were described as men, in most cases with dark hair and between the ages 30 and 50, and they commonly spoke with an accent.

Police confirmed that in every case except one, the women involved were between the ages of 19 and 25, most were travelling in the front seat and the alleged attacks happened when there was only one passenger in the car.

In many cases, the accused said he didn't want to be paid and attempted to flatter the women, who were typically picked up at night in the downtown core during the spring and summer months.

In a majority of the cases, the alleged sexual assaults involved touching in sexual manner and forcible kissing, police said.

In three of the most recent cases, police described the unknown suspects as "Middle Eastern men," prompting critics to suggest that such a description was not only useless in terms of physical attributes, but also relied on damaging stereotypes about the region.

Hernden said the term was purposely left out of the latest statement.

"The Middle Eastern moniker was provided by the victims -- but it's not helpful," he said.

"When you look at the Middle East, there's 17 different countries that make up that area. The physical attributes are so varied, it doesn't offer any help in term of identification."

Jackie Stevens, executive director of the Avalon Sexual Assault Centre in Halifax, said her group has been hearing about sexual assaults and inappropriate conduct by cab drivers for years.

"Given the number of reported incidents of sexual assaults in general, it's interesting to wonder if this is still a low number in terms of the actual number of sexual assaults ... in cabs," Stevens said in an interview.

"And sometimes people aren't sure if it's something they should report, and they may not immediately define it as sexual assault ... Also, if it's a situation where people have been drinking, they may not recollect what happened until after they sober up. There's lots of factors."

Police also issued a series of safety tips:

Call a taxi instead of hailing one to ensure there is a record of your request.

Make a note or take a photo of the taxi company name and roof light number.

Make sure the cab has a prominently displayed licence, driver photo and meter.

Sit in the back seat on the passenger side, the farthest position from the driver and curb-side in the event you need to exit quickly.

Have your cellphone handy and call 9-1-1 if you feel uncomfortable with what is going on.

Stevens welcomed the tips, saying it was clear police were careful to avoid suggesting that the victims' behaviour was somehow to blame.

"In this case, the police are being very clear the problem is the cab drivers committing sexual offences and not the people getting into those cabs," she said, adding that she's heard that women are sometimes erroneously told that sitting in the front seat of a cab is the safe way of travelling.

About 1,000 taxis are driven by about 1,500 drivers in the Halifax region, Hernden said.

There were two cases involving alleged sexual assaults in taxis in 2012, one in 2013, one in 2014, three in 2015 and five to date in 2016, police said.