With an estimated 400,000 people lining the downtown Miami streets, the Heat held their parade and an in-arena rally afterward Monday. LeBron James stood atop a double-decker bus with a cigar in his mouth for the parade. Shane Battier blew kisses to the crowd, Dwyane Wade raised three fingers aloft, and Chris Andersen flapped his arms in a nod to his ‘‘Birdman’’ moniker. Miami became the sixth franchise in NBA history to win consecutive championships, after topping the San Antonio Spurs. Police reported no major problems, and bomb- and drug-sniffing dogs were spotted working their way through the crowd. City officials banned fans from carrying backpacks, though several were spotted along the route and some people were searched randomly for security reasons. Full story for BostonGlobe.com subscribers.