SALT LAKE CITY — A 19-year-old man was paid a visit by two Secret Service agents after neighbors complained about an anti-President Bush sticker on his car.

The black-and-white, postcard-sized paper printed off a Web site and taped on Derek Kjar's car had a cartoonish depiction of Bush's head wearing a crown, with the words "King George — off with his head."

Stickers of that image are widely available on the Internet.

Lon Garner, special agent in charge of the Secret Service's Denver field office, confirmed that Kjar was investigated, but said agents had ruled out a threat to the president.

He said it was the agency's job to investigate all reported threats to figures under Secret Service protection — including Democratic presidential candidate John Kerry.

"We are bound by law," Garner said. "We take them very seriously, regardless of who the protectee is."

Still, the visit put a scare in Kjar, and has First Amendment experts crying foul.

"It's political hyperbole," said David Hudson, a research attorney with the First Amendment Center. "However distasteful you might think it is, it's pure political speech."

Kjar said two agents visited him at his job at a dry-cleaning service and interviewed him for about an hour and 15 minutes. He said they asked him about a broad range of things, including whether he had any ties to terrorist groups or enjoyed reading historical accounts of assassinations.

They also asked Kjar about his friends and family, and even wanted to know how he split up bills with his roommates, he said.

He said the agents asked him to take the paper off his car and give it to them, and didn't gave it back.

Kjar said he feared the agents were going to "take me away."

Now, he thinks his right to free speech was violated, but he said he wasn't sure if he would pursue legal action.

"I kind of feel trapped, like I'm not allowed to express my opinions. I felt like my freedom of speech was shot to hell right there."

In the meantime, Kjar said he was concerned about having a file with the Secret Service. He said the agents showed up with a stack of paperwork containing his personal information and the photograph from his state-issued driver's license.

"I feel like if I go to an airport, I'm going to be screened more," he said. "If anything ever happens in Utah, I'll be one of the first people they come to."