The Justin Bieber Purpose album graffiti that has been popping up in San Francisco is being investigated. In an effort to figure out exactly who is behind the incidents, city attorney Dennis Herrera sent a letter to Universal Music Group this past Monday (Dec. 28). In the letter, Herrera expresses that the graffiti is suspected to have been done in spray paint and will not budge from sidewalks in Haight-Ashbury and other neighborhoods. In San Francisco, past marketing campaigns have been done using chalk.

Herrera claims that although some of the graffiti has been removed, it cost a great deal (though he was dodgy on the exact expense). His office additionally sent eight photographs of the graffiti to Universal for help. City officials have been plagued with complaints about the graffiti.

On the complaints received about the graffiti Herrera said in the letter shared with Billboard, "This prohibited marketing practice illegally exploits our city's walkable neighborhoods and robust tourism, intentionally creates visual distractions that pose risks to pedestrians on busy rights of way, and irresponsibly tells our youth that likeminded lawlessness and contempt for public property are condoned and encouraged by its beneficiaries."

This is not the first time that Herrera's office has gone after a marketing campaign, in 2010 they pushed a $45,000 penalty fee on a advertising agency who had glued decals to sidewalks to promote an internet game.

In other Bieber news, the "Love Yourself" crooner encouraged his fans to pay attention to the National Health Service Choir's charity single "A Bridge Over You," during the holidays. In a social media campaign Bieber managed to bring the charity single to No. 1, over his "Love Yourself," in the annual U.K. Christmas race. Bieber brought the Christmas cheer by deciding that it was "ok not to be No. 1" for a week.

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