SAN JOSE, Calif. » Police officers and FBI agents are raiding 11 Vietnamese cafes and bars in a crackdown on illegal video gambling machines in a Northern California city.

San Jose Police Lt. Mike Sullivan says search warrants were simultaneously served at 11 locations Tuesday.

Sullivan says the raids capped a year and a half of investigations revolving around illicit gambling and "dozens of cases of violence" linked to struggles over money.

The San Jose Mercury News reported Tuesday that details on the operation and on the businesses targeted will be released once the raids are completed.

San Jose Police Sgt. Todd Trayer and a counterpart from the FBI’s San Jose office were reviewing a string of shootings and stabbings connected to bars and cafes in November 2013 when they saw a pattern.

They began a joint investigation that led to Tuesday’s raids.