BOSTON -- The bombing of the Boston Marathon shocked a nation, bloodied a city and stunned its proud police force. Two men — brothers, it turned out — allegedly were able to walk within yards of the finish line on Boylston Street unchallenged by security, drop two bags containing pressure cooker bombs and stroll away moments before they exploded.
The Boston Police Department has vowed it will not happen again, that the 2014 Marathon will be different. Police departments from New Jersey to Maine are sending in units: SWAT units, bomb squads, aerial surveillance and K-9 teams.
Boston Police Commissioner William Evans, who has run the Boston Marathon 18 times, will not be running on Monday because he's got a job to do. As the new head of the Boston Police Department, he is charged with protecting what he says is supposed to a "real fun family day."
"It's Patriots' Day," he says of the state holiday on which the race is run each year. "It's what it means to be a Bostonian here, it really is."
To keep runners and spectators safe, he, his officers and members of at least 14other law enforcement agencies from Massachusetts and beyond will deploy a diverse and intimidating array of security resources.
Among other things, officers will erect 8,000 steel barricades -- 1,200 more than last year - around the race route, man at least 40 checkpoints and command four times the number of K-9 units as were present at last year's race.
Another 3,500 uniformed and undercover officers will spread out along the marathon route, looking for anything suspicious in the crowd of spectators or among the 36,000 runners - 9,000 more than usual -- expected to start the race.
Those trained eyes will be augmented by 40 new security cameras, both fixed and mobile. They will send video to a fleet of upgraded command post trucks and the Boston PD's 180,000-square-foot glass encased headquarters.
Watch Stephanie Gosk's report on marathon security Sunday on NBC Nightly News
Evans says the plan aims to attain the perfect balance of technology and boots on the ground, "We have plenty of undercover officers out there, but technology, you know, is going play a big part," he told NBC News. "We have a lot more video surveillance out there."
But he said he doesn't want an outsized security presence that will make people who come to watch the race and cheer on the competitors feel uncomfortable.
"I don't want people to be intimidated by coming here, so it's going look like it did last year, but there's going be a lot more assets that people won't see" he said.
Because the two pressure-cooker bombs that exploded near the finish line last year, killing three people and injuring more than 260 others, were concealed in backpacks, officials are limiting or banning carry-alongs this year.
Spectators who pass the security checkpoints will be allowed to bring belongings only in clear bags, not backpacks or purses.
Runners also will have to contend with new rules. If they want to bring a change of clothes, they must put them in a special clear bag provided by race organizers and drop them off at a "gear check" area at the finish line before the race. And during the race, they can carry only fanny packs smaller than 5 by 15 by 5 inches will be allowed, along with drinking bottles holding only 1 liter.
Sending in the hounds
Dogs will play a major role in trying to head off any threat involving explosives.
Officer Troy Caisey of the Boston PD's Special Operations Division trains the dogs that will sniff their way along the race route, accompanied by K-9 teams from the Massachusetts State Police, as well as law enforcement agencies from Rhode Island, Connecticut and Vermont.
The canine contingent's involvement isn't limited to prevention.
Caisey recalled that when the bombs went off last year, handlers and their dogs sprinted toward the blast site. "All the bomb dog handlers started doing was looking for secondary devices," he said.
Caisey will be working with a fleet-footed German Shepherd named Bronson. Bronson, sporting his black and grey Boston Police Department uniform, will be patrolling checking "backpacks, boxes, any type of metal structures that are on the road or on the sidewalk." And it's all about the scent, "anything that something that can be hidden in, we're making sure we at least put a dog's nose on it."
If the dogs detect any whiff of explosives, they are trained to sit down immediately and "point" to the source of the suspicious scent with the tip of their nose. The next call would go to Boston police Sgt. Chris Connolly's team.
Connolly's bomb squad will be ready if that call comes. Members of the unit already have responded to several reports of suspicious packages this week around the finish line.
Augmented by bomb squads from the New York and New Jersey state police, the New York Police Department, the FBI and the military, Connolly is loaded for bear this year. He has five more bomb suits and six more vehicles than last year at his disposal. He also has a fleet of robots, X-ray machines to take a safe look on what's inside a suspicious backpack, and the tools to disrupt a potential bomb before anyone gets hurt.
Most important, he has highly trained officers willing to put on an 85-pound suit and helmet and step within inches of life-threatening danger to get the job done.
One of the men prepared to step into the green-and- black Kevlar-laden suit is Derek Russo. He takes his assignment seriously. "It's a personal thing - for all Bostonians," he says. "We all want to be out on the front lines, we want to make sure this doesn't happen again."
When asked what's in his head for this year's marathon, he replies, "Preparation and safety, that's it."
That mindset fits with the commissioner's message to his department, "Let's put our best game face on and let's do what we always do and that's a great job that all the citizens of Boston can be proud of."
And while Evans won't be trying to beat his time of 3 hours and 34 minutes that he ran last year, he's hopeful he'll still enjoy this year's race.
"I'm confident it will be the day it's always been, which is a great family day."