Most of the scrawling vandalism is gang-affiliated, and police need help from the public to catch those responsible, said officer Mike Hicks, who was recently assigned to graffiti enforcement.
"There's a war on the street, and graffiti is one of the ways (gang members) advertise their war," Hicks said. "The neighbors know who it is, but they're too afraid to report it."
Hicks said they'll prowl in unmarked police cars at night to keep an eye on four neighborhoods known for high graffiti activity.
Team members plan to watch those spots for the next few weeks. They went out Tuesday night, but made no arrests.
Officer Dave Wallace said that the presence of police can act as a deterrent for some taggers, but not all.
"Some of these guys are flagrant in what they do," Wallace said.
Hicks said police can't stop the graffiti alone, and he encourages residents to call and report the crimes. He said the rise in graffiti is directly related to an increase in gang activity this year.
City employees already have cleaned off or painted over 626,000 square feet of graffiti for fiscal year 2003-04, Hicks said. In the same period of time, the city has spent $268,000 on cleanups and enforcement, he said.
The city expects to cover 800,000 square feet of graffiti in fiscal year 2004-05.
"This is the worst year we've had," Hicks said. "We have some areas that have to be painted on a weekly, if not daily, basis."
The Modesto Police Department is asking the public to call and report any graffiti activity at 342-2259.