A Pennsylvania newspaper unwittingly published a classified ad calling for the assassination of President Barack Obama earlier this week, and is now issuing an apology.

John Elchert, publisher of Tthe Warren Times Observer said Friday that the ad which ran Thursday read:

May Obama follow in the steps of Lincoln, Garfield, McKinley and Kennedy!"

For those unaware, all four were Presidents assassinated while in office. Elchert said that the paper's advertising staff had failed to realize the historical connection, and that is how the ad slipped through the cracks and got published.

The newspaper has since turned over information to the police, and the individual who placed the ad is now the subject of a Secret Service investigation.

The Times Observer apologized in a brief note in Friday's paper "for the oversight."