04/16/2013 04:52 EDT | Updated 04/17/2013 01:48 EDT

Boston Marathon Bombings: Mystery Man On Roof Sparks Speculation (VIDEO)

A Canadian may have given U.S. federal authorities an intriguing lead in the investigation of the Boston Marathon bombings.

Sandra Sukstorf, who works for the Canadian Forces, was in the city's Lenox hotel waiting for her husband to finish the race when the blasts erupted, the National Post reports.

Yesterday afternoon, a pair of bombs tore through the crowd around the finish line, killing three people and injuring at least 170.

In the immediate aftermath, Sukstorf reportedly captured a grainy image of three figures on the roof of the Charlesmark Hotel across the street -- figures that stood at the edge of the roof directly above the finish line, before retreating out of sight.

Sukstorf has shared her footage with authorities after a broad appeal for witnesses who to share videos and photos with the investigation.

Another similar photo, this time of a single man walking on another nearby roof is also lighting up the speculation on social media.

Marathon spectator Dan Lampariello, who captured the photo, was there to cheer his aunt across the finish line when the first explosion occurred, according to ABC News

"I was about 200 feet from the finish line … right in front of the Mandarin Hotel," he told ABC. "We thought maybe it was fireworks at first, but when we saw the second explosion we definitely knew that something was wrong.”

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Sandra Sukstorf caught more than a potential lead in the bombing investigation. Perhaps more importantly, she caught the heroism of those caught up in the attack's aftermath.

She told the Washington Post how emergency responders rallied quickly, tearing down snarled fences "like Hercules."

"I just had this feeling there was going to be another one, so I left the room immediately and went to the stairwell."

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