There were signs comparing President Barack Obama to a Nazi and showing him with an Adolf Hitler-style mustache, but federal officials believe another sign referencing the president and his family went too far.
Washington County Sheriff's Capt. Peter Lazich said the sign also read, "Death to Michelle and her two stupid kids."
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Lazich said U.S. Secret Service agents took the unidentified 51-year-old man into custody Wednesday afternoon after deputies detained him near the entrance to Hagerstown Community College.
Obama was not at the meeting held Wednesday by Maryland Democratic Sen. Ben Cardin.
Barbara Golden, special agent in charge of the agency's Baltimore field office, said Thursday that an investigation is ongoing but declined further comment. A spokesman at the agency's Washington headquarters also declined to discuss the investigation.
Police said there were no other arrests among the nearly 1,000 people, some carrying protest signs, who came to the college for
the meeting or demonstrated off-campus.
Cardin's national communications director, Sue Walitsky, called the incident "unfortunate." She said she was unaware of it until