A man reportedly posted threatening, expletive-filled letters on tents at a Mission District encampment Friday afternoon, a human rights organizer said.

Shortly after 1:45 p.m., a homelessness service provider found letters on multiple tents at an encampment beside the Duboce skate park between Mission and Valencia streets, according to Kelley Cutler of the Coalition on Homelessness.

Dated Feb. 9, the letter read in-part, "If you are still here after dark tonight, the hunters will become the hunted. We will pound you, burn you, beat you and f-- you up if you are within 100 yards of the park starting after sun down tonight." Signed, "The neighbors."

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Cutler said about five people at the small encampment had the letters. One man said he was awoken after a man posted the note to his tent, and the man with the letters pepper-sprayed him. The homeless man had traces of colored spray on his body, Cutler said. She was uncertain if others had witnessed the altercation.

Encampment residents told Cutler that the man with the letters got into a black SUV that they had frequently seen around the neighborhood. The residents recorded the individual's license plate number, which the Coalition on Homelessness forwarded to San Francisco police. Police could not immediately be reached to comment.

Cutler says the man was not a member of the encampment.

"Folks that are experiencing homelessness are targeted a lot," she said. "[Being threatened] is not that unusual, though this sort of letter is."

Michelle Robertson is an SFGATE staff writer. Email her at mrobertson@sfchronicle.com or find her on Twitter at @mrobertsonsf.