An aide to US President George W. Bush resigned Friday over charges he had resorted to plagiarism in his writings.

Timothy Goeglein, who served as a liaison between Bush and religious organizations, “accepted responsibility for the columns published under his name in his local newspaper, and has apologized for not upholding the standards expected by the President,” White House spokeswoman Dana Perino said in a statement.

An internal investigation conducted by The News-Sentinel, a newspaper published in Fort Wayne, Indiana, has revealed that 20 out of 38 columns published by Goeglein between 2000 and 2008 had portions copied from other sources without attribution.