Teen idol Justin Bieber's latest album, "Purpose," may be garnering big sales, but San Francisco's city attorney is on the hunt for those responsible for what he calls a "guerilla marketing" campaign of sidewalk graffiti promoting the album.

The ads, which City Attorney Dennis Herrera said seemed to have been spray-painted at several locations, contain the words "Justin Bieber," "Purpose" and "#Nov13," presumably in reference to the album's November release date.

"Our sidewalks in San Francisco are not canvasses for corporate advertising," Herrera said in a letter to executives at Def Jam Recordings and Universal Music Group, Bieber's record label and distribution company.

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Herrera, in the letter, said he would "aggressively pursue all available penalties and costs from those responsible."

He said the vandalism "irresponsibly tells our youth that likeminded lawlessness and contempt for public property are condoned and encouraged by its beneficiaries."

Representatives for Universal Music Group and Def Jam, which is part of Universal, could not be immediately reached for comment.

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The Bieber campaign stencils appeared to have been done in permanent spray paint and did not wash away in recent rains, Herrera said.

Similar sidewalk graffiti appeared in Manhattan's East Village neighborhood in November around the time of the album's release, a Reuters witness reported.

Herrera's office said the album campaign was not the first to plague San Francisco streets and the issue has re-emerged over the past year, triggering complaints from residents.

Previous vandals used chalk, he said.

Herrera said his office has previously secured financial settlements for similar campaigns, which have been waged by IBM, NBC Universal, Turner Broadcasting and Zynga. He said civil penalties for each instance of graffiti could run up to $2,500.

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Ian Kerr, a sales associate with advertising firm OUTFRONT Media, said advertising on a San Francisco bus shelter could cost around $400 for a four-week period, while a highway-side billboard could cost anywhere between $25,000 and $50,000.

In October, Bieber posted images to his Instagram account purporting to show elaborate graffiti art in several cities of the track names on the album, including one said to have been drawn in San Francisco. The city attorney's office did not directly address that image.

The album, Bieber's fourth and which has scored the best-selling debut so far in the singer's career, reached the top of the U.S. Billboard 200 album chart, selling 520,000 albums, 602,000 songs and being streamed 100 million times in its first week.