The FBI has confirmed it is now seeking two men in connection with the Boston Marathon bombings, who can be seen in video footage of the attacks on Monday.
According to Homeland Security Secretary Janet Napolitano, the FBI wants to speak with two men although she has refused to label them officially as "suspects" at this stage.
Napolitano also refused to provide any details of the men's appearance or what they can exactly be seen doing in the video footage evidence.
The Homeland Security Secretary was speaking to the House Homeland Security Committee on Thursday morning, explaining that "there is some video that raised the question" of two men the FBI would like to interview.
Napolitano also confirmed that the FBI still is not clear on whether the Boston bombings were the work of domestic or foreign terrorists, although she also added that their investigations were moving forward at a fast pace.
It has now been confirmed that three people died and more than 180 others were injured in the twin blasts near the finish line of the Boston Marathon on Monday.
Two bomb devices are thought to have been used a few hundred feet apart and were detonated about 12 seconds apart.
At least one of the bombs was packed inside a pressure cooker filled with ball bearings and metal nails to cause an optimal amount of death and damage to those in the vicinity of the blast.
On Wednesday, it emerged that video footage had been found from at least two sources that seemingly identified a man leaving a bag at the location of the second bomb. In the immediate aftermath of that news breaking, CNN reported that a suspect had been arrested, however, within an hour that report had been debunked by various official sources, and as of Thursday morning, no arrests have been made.
Here is a video news report in the aftermath of the Boston bombings: