Bomb Sniffing Dogs, Spotters on Roofs Before Explosions --UM Coach 15 Apr 2013 University of Mobile's Cross Country Coach, who was near the finish line of the Boston Marathon when a series of explosions went off, said he thought it was odd there were bomb sniffing dogs at the start and finish lines. "They kept making announcements to the participants do not worry, it's just a training exercise," Coach Ali Stevenson told Local 15. Stevenson said he saw law enforcement spotters on the roofs at the start of the race. He's been in plenty of marathons in Chicago, D.C., Chicago, London and other major metropolitan areas but has never seen that level of security before. "Evidently, I don't believe they were just having a training exercise," Stevenson said. "I think they must have had some sort of threat or suspicion called in."