San Francisco’s district attorney announced a string of felony charges against graffiti vandals on Tuesday.

He says the city is cracking down on the worst vandals in the city. A grand jury has indicted seven high-profile graffiti vandals.

The district attorney accuses them of tagging and vandalizing buildings in the city repeatedly, calling them the people who “drive” the problem in San Francisco.

Aside from anything else, district attorney George Gascon says it’s a very expensive problem.

Gascon says there’s been lots of property damage.

And it’s particularly harmful to small business owners who find it hard to keep coming up with the cash to clean things up.

Authorities say most of the damage is being done by taggers as opposed to hardcore gang graffiti.