An explosives sniffing dog died this morning after falling from a ramp at the George R. Brown Convention Center in downtown Houston. The dog, Mikey, was part of a U.S. Alcohol, Tobacco, Firearms and Explosives unit involved in a security sweep of the convention center in preparation for the NBA All-Star game, said Franceska Perot, spokeswoman for ATF. Perot said about 1:30 a.m. the unit was taking a break and the dog, a Labrador, was being put into the back of a truck when he suddenly bolted and went over the edge of a ramp. The dog fell about 55...