Police have released an image of the bombs that triggered the terror at the Boston Marathon on Monday.The photos released show what's left of the explosives.
Police say the devices were pressure cookers, one containing small metal pellets and ball bearings, the other packed with nails.
The two bombs went off within 10 seconds of each other near the finish line. The bombs were left in black backpacks or duffel bags and put on the ground. Investigators also found a circuit board they believe was used to detonate the explosives.
Authorities say the marathon route was swept twice by bomb technicians before the deadly blast. The FBI has received 2000 tips so far and has no suspects right now.
Several unions in Boston are hoping a $50,000 reward will help lead to an arrest.
Detectives, Police, and Fire unions are offering the money to anyone with information that leads to the bomber.