and public transit hubs and shopping malls, airports and los angeles international travelers will be seeing bomb-sniffing dog, extra police and security beefed up. in san francisco, authorities are meeting to talk about an upcoming race in that city, the beta breakers race to talk about security there, all around the state here people are being asked to report anything suspicious to authorities and to be on heightened alert here. >> security concerns extending around the world, as well. especially across the pond in london, the setting for two major public events this week. >> expect a major military presence at the elaborate funeral of former prime minister margaret thatcher set for tomorrow and police are reviewing plans for london's own marathon taking place sunday. >> when we come back stories breaking overnight include a u.s. military accident in south korea. >>> then more from boston including new videos of the bombing emerging overnight. >>> what is it about this week in april? several major tragedies have all had this week in common. we'll get into that coming up. [ male announcer ] now we can all be at the corner of "just another prescription" and "sweet, something