Security at this year's Chicago Marathon will be tighter than ever after April's bombing at the Boston Marathon.
Chicago Police Superintendent Garry McCarthy said at a news conference Tuesday that there is no known threat to Sunday's marathon or to the city.
But still, Chicago officials want to be prepared. McCarthy says there will be more bomb-sniffing dogs along the 26.2-mile route. He says there will be undercover officers and the city will use its extensive surveillance camera system to watch virtually every foot of the course. About 45,000 runners are expected to participate.
Police say for the first time any unattended bags along the race route or at the start and finish lines in Grant Park will be collected and discarded.