You never know what some people do on their off days.

Lower East Side graff artist RD 357 was busted for leaving his tag all over Manhattan and it turns out he works for the city, police said this weekend.

Robert Dyer, 49, who works for the New York City Department of Health and Mental Hygiene, was arrested Wednesday and charged with 82 counts of making graffiti. The bust concluded a 6-month investigation to track down the vandal.

The famed all-city writer has 13 prior arrests dating all the way back to 1982 when he was just 15 years old. Over the span of two decades, RD, along with the rest of the 357 Crew have went all city and have become a mainstay in NYC graffiti.

Dyer’s next court hearing is Sept. 20.