Police say two rival gangs of street-level drug dealers - Fresh Off the Boat (FOB) and the FOB Killers - have been fighting a pitched battle for the past six years that has been driving the city's rising homicide numbers."I think what is relatively clear is the violence we saw in 2008 between these two factions is retaliatory. One incident has, within weeks or months, led to a second incident," Deputy Chief Murray Stooke said this week."We are concerned that this back-and-forth retaliatory conflict will continue in 2009."Just over 14 hours after police were called to an unrelated homicide Thursday - the city's first of 2009 - at least two gunmen walked into Bolsa, a Vietnamese restaurant in the city's southeast - and opened fire at a table in the middle of the room. Police found one man dead, face down, in the parking lot outside, and two more corpses inside the restaurant.One of the victims was identified as Sanjeev Mann, a member of the FOB Killers gang.In December 2008, a deportation hearing was held for Calgarian Jackie Tran, who police have identified as a member of FOB Killers. The hearing provided a rare public airing of the circumstances that led to the deadly gang rivalry.

The two gangs emerged from a group of high school friends who dealt drugs together, but later went their separate ways. Conflicts between the two groups escalated quickly from knife fights to gun battles, endangering bystanders and claiming at least 15 lives in the past six years.In one recent violent episode, a gun battle between city gangsters erupted Nov. 16, 2008 in Calgary's Chinatown. Police said the shooting started when the occupants of an SUV pulled up alongside a car and opened fire, wounding several people. Two of the victims are allegedly associated with the local Fresh Off the Boat gang.Just weeks later, a drive-by shooting on a crowded crosstown highway prompted Calgary police to take the rare step of warning friends, family members and associates of known gang members that they'd become targets of retaliatory attacks."These two groups have escalated to the point now that if you are a member of one of these two gangs, if you're an associate, if you're a girlfriend, if you happen to be in the same vehicle with members from these two groups, you are at risk of being a victim of a shooting or a homicide," said acting Staff Sgt. Gord Eiriksson.Calgary police have identified 400 known gang members and associates who operate within the city.