High school yearbooks were recalled so that administrators could black out a joke caption under one student's picture: "most likely to assassinate President Bush."

Mesa Ridge High School (search) officials recalled about 100 yearbooks earlier this month and had staffers use markers to obscure the words in them and in the still-undistributed copies. The Secret Service even launched an investigation.

"They kind of ruined our yearbook," said Christina Tredway, who just graduated from the school just south of Colorado Springs. Most students thought the blacking-out was a bad idea since the caption obviously was a joke, she said.

Widefield School District (search) officials called the caption a prank that wasn't caught before the yearbooks were printed, and district spokesman James Drew said future yearbooks will be triple-checked before printing.

Lon Garner, special agent in charge of the Secret Service's Denver District, said the agency would look into the incident because all threats against the president must be investigated.

"That's our mission," he said. "That's what we do."

There were several other joke captions in the book, including "most likely to forget his gown at graduation." Names of those involved were not released.