The elite runners had long since passed through the finish line and gone their separate ways. The best part of the Boston Marathon — where the rest of the runners were either realizing lifelong dreams or finishing up their races for a myriad of noble causes — was under way.Suddenly a blast shattered the festive air at the finish line. Then, seconds later, another one. And at that moment we all knew. Terrorists — who knew from where? — had found the City of Boston, and attacked one of its most venerable institutions. The blasts killed three people, and a fourth, an MIT policeman, was allegedly slain by the same brothers suspected of detonating the two bombs.The explosions also seriously injured and maimed more than 200 spectators and runners with shrapnel that ripped through their bodies, robbing them of their limbs and changing their lives forever.In the ensuing four days, police pieced together enough security camera footage to identify the perpetrators, at least by face. And by Friday, the suspects –Tamerlan and Dzhokhar Tsarnaev — had staged a gun/explosives battle with police in Cambridge and Watertown (claiming the life of MIT officer Sean Collier and seriously wounding MBTA policeman Richard Donahue). Tamerlan, the older, ended up dead and, after a daylong area-wide lockdown, Dzhokhar, the younger, was captured.Boston has had its dark days and moments, from fires to racial strife to murders. But the idea of the same type of terrorism that felled New York?s twin towers, killing almost 3,000 people, touching this city was about as dark as it could ever get.But out of that darkness there appeared an unusually bright star.Nelson Mandela, who died earlier this month, once said that athletics represent a beacon that can unite and heal conflicting elements of society. Nowhere did that light shine brighter than within the Boston sports establishment — most notably the Red Sox.This is the story of how sports in Boston helped heal the gaping emotional wound the Marathon bombing created.It was Will Middlebrooks of the Red Sox who first tweeted the words “Boston Strong” in the moments after the team — which by then was on a plane headed for Cleveland — heard about the bombing. The slogan immediately took hold.In the first Bruins game after the bombing, singer Rene Rancourt stopped in the middle of his rendition of the National Anthem to let the sellout crowd sing it a capella. Many of those there were moved to tears. It would be most fair to suggest the Bruins, perhaps spurred on by the tragedy, made an extra effort to refuse to go quietly when trailing, 4-1, in Game 7 of a first-round Stanley Cup playoff series against the Maple Leafs. They staged a stunning comeback, won in overtime, and rode the emotion all the way to the Stanley Cup Finals.All of the Boston-area teams took time to honor the victims and first responders. But it was David Ortiz — perhaps as a portent of things to come from him — who sounded the first succinct battle cry in response to the tragedies. On the day after Dzhokhar Tsarnaev?s capture, during an elaborate pregame ceremony honoring the first responders, Boston?s designated hitter spoke — very extemporaneously.?This is our (bleeping) city,” Ortiz shouted (much to the overwhelming approval of the sellout Fenway Park crowd). Not only did he emerge from that impromptu speech a hero, he emerged unscathed in terms of legal repercussions.Daniel Nava made sure the emotion of the day wasn?t left hanging, as his three-run homer late in the game beat the Kansas City Royals.From then on, the Red Sox owned the (bleeping) city. And they went about taking its citizens? minds off this terrible tragedy, as much as that was possible. They went from a team impossible to like to a team impossible to dislike … and even more impossible to ignore.The team?s reemergence from its own darkness had begun within weeks after the conclusion of its disastrous, 69-93 season in 2012. It fired the divisive Bobby Valentine and