Vancouver police were caught off guard by the riot that followed Game 7 of the Stanley Cup finals, in part because steps taken ahead of Game 6 to cut off the supply of booze were so successful.

Early liquor store closures "were a huge success" said Vancouver police deputy chief constable Doug LePard in a June 14 email, the morning after the Vancouver Canucks lost to Boston.

"Even before it became clear the Canucks were going to get blown out, there was a very noticeable reduction in alcohol-related problems such as gross intoxication (and) fights," he wrote to other police and government officials. The emails and his summary of an earlier conference call between the Vancouver police, ambulance and liquor officials were released on Thursday.

Vancouver liquor stores closed early before Game 6 in response to the chaos that followed Game 5 -- an unruly spree of fights and "grossly intoxicated young people" fuelled by an explosion of liquor sales after the game, according to LePard's summary.

There was "lots of broken glass, assaults, fights and people being hit with bottles" and "young men running around randomly punching people in the face, including girls," he added.

Liquor stores closed early ahead of Game 7, but after the Canucks lost 4-0 to Boston the resulting riot was driven by people who were already drunk or who had loaded up on liquor beforehand, expecting the stores would be closed.

Police had expected some "angry, depressed people" and some hooliganism but not a full-scale riot.

The investigation into the riot continues, and on Thursday Vancouver police released photos of another 12 suspects -- dubbed "the dirty dozen" -- taken amid the June 15 mayhem.

Investigators have posted photos of 101 suspects in total to the Riot 2011 website, of which 52 have either been arrested or turned themselves in. Two of the dirty dozen have already been identified.

LePard said Thursday that he hopes to bring "the first wave of charges" by the end of the month.

"The public's response to the postings has been overwhelming and we are grateful for that. However, we also realize that public interest wanes and it is challenging to ask people to keep returning to our website," he said. The site received almost one million hits within days of launching, and within weeks it had generated about 400 new tips.

Suspects are being encouraged to plead guilty in order to lessen the load on B.C.'s courts. "It's always our objective to build a case strong enough that the accused feels he has no choice but to plead guilty," LePard told reporters.

With files from CTV British Columbia