On 30 April 2015 , the day before the race was due to have taken place , local authorities announced that it had been cancelled due to " indications of a possible threat to the population " . A couple , one of whom was described as a " suspected Islamic extremist " , were arrested the previous day at their home in Oberursel , which is along the race route . The couple arrested were identified as Halil D. , 35 , a German citizen of Turkish origin , and Senay D. , 34 , thought to be a Turkish citizen . Various items were found in their house , including a homemade pipe bomb , bomb-making materials , an automatic rifle , bazooka ammunition and a canister full of petrol . One of the couple had apparently bought hydrogen peroxide and alcohol at a hardware shop and had been seen exploring a forest along the race route . He had connections to Salafists in Frankfurt , including the group Dawa FFM . The German newspaper '' Die Welt '' suggested that he was involved with Al-Qaida , specifically Al-Qaeda in the Islamic Maghreb ( AQIM ) . According to German police the couple had also travelled to Spain to meet with members of Sharia4Spain . It has also been suggested that there may have been connections to Adem Yilmaz , one of those convicted as part of a bomb plot in 2007
bomb plot in 2007
2007 bomb plot in Germany
2015 Eschborn-Frankfurt City Loop