Federal agents suspect parts from radio-controlled hobby cars were used to construct the IEDs used in the Boston Marathon bombings on Monday.
Hobby store owners told ABC News federal agents questioned them about the use of these hobby components based on evidence photos from the scene. One widely circulated photo shows a red and black wire connected to a Tenergy battery, which is used in battery packs for DuraTrax toy cars.
The explosive devices, which were housed in at least one pressure cooker, killed three and wounded at least 170 at the marathon's finish line.
On Thursday, the FBI released photos showing two suspects and asked for the public's help in identifying these two young men.