It has been alleged that Headley made periodic trips to Pakistan for Lashkar-e-Taiba training while simultaneously working as an informant for the U.S. Drug Enforcement Administration (DEA), but this is disputed.[3][4] Under the direction of Lashkar chiefs, Headley performed five spying missions in Mumbai to scout targets for the attacks, which killed 168 people. The following year, he performed a similar mission in Copenhagen to help plan an attack against the Danish newspaper Jyllands-Posten, which had published cartoons of Muhammad. He was arrested at O'Hare International Airport in Chicago while on his way to Pakistan in October 2009.[3][5]