CHICAGO, Jan. 27 (UPI) -- The more than 68,000 members of Chicago-area gangs often rely on the Internet to coordinate crimes and provoke rival gang members, a law enforcement book says.
The Chicago Crime Commission Gang Book says gang members use computers and smartphones for "cybertagging" -- graffiti on Web sites -- and sometimes boast of their crimes online, the Chicago Sun-Times reported Friday.
"They're tagging Web sites with information that is provocative and incites violence," said Jody Weis, former Chicago police superintendent and president of the commission.
"They can talk to their whole gang this fast," Weis said, snapping his fingers. "They can send a message: 'Everybody meet at this corner at this time.' And everybody's got it."
Two-thirds of school violence is linked to social-media sites, Weis said.
"You and I get in an argument on Facebook and the next thing you know, I'm shooting your sister or you're shooting my brother," he said.
Weis said in a news release the 320-page book serves as a training tool for law enforcement, educators, parents and businesses, the Chicago Tribune reported.
Web communication sometimes enables law enforcement to gain information about activities of the 73 street gangs, the book says.
The Sun-Times said the book pointed to gang members' Web communication about shooting at police officers, threatening a witnesses in a murder trial and boasting about drug dealing, and last year Chicago police monitored social media sites to battle young people robbing and assaulting people in the downtown area.
"Social media is now used as part of good police work," said Leo Schmitz, commander of the Englewood District and former head of gang enforcement for the Chicago Police Department.