The scenario had been carefully planned: A terrorist group prepared to hurt vast numbers of people around Boston would leave backpacks filled with explosives at Faneuil Hall, the Seaport District, and in other towns, spreading waves of panic and fear. Detectives would have to catch the culprits.
Months of painstaking planning had gone into the exercise, dubbed “Operation Urban Shield,” meant to train dozens of detectives in the Greater Boston area to work together to thwart a terrorist threat. The hypothetical terrorist group was even given a name: Free America Citizens, a home-grown cadre of militiamen whose logo would be a metal skull wearing an Uncle Sam hat and a furious expression, according to a copy of the plans obtained by the Boston Globe.
But two months before the training exercise was to take place, the city was hit with a real terrorist attack executed in a frighteningly similar fashion. The chaos of the Boston Marathon bombings disrupted plans for the exercise, initially scheduled for this weekend, forcing police to postpone. Now officials must retool aspects of the training.
“The real thing happened before we were able to execute,” said a law enforcement official with direct knowledge of the planned exercise. “We’ve already been tested.”
This would have been the third year for Urban Shield, a 24-hour federally funded training exercise meant to test the response of police and other public safety personnel in a large-scale emergency, such as a toxic spill or a natural disaster.

Last fall, a slew of agencies including Boston police and other police departments, the Coast Guard, and the MBTA joined forces to confront a simulated armed bank robbery in which the robbers were trying to escape with hostages.
For this year’s training, the agencies wanted to test the investigative skills of their detectives, as well as their ability to work with detectives in other cities, and share intelligence, said the official, who spoke on condition of anonymity because details of the planned exercise were confidential.
The training, funded by a $200,000 Homeland Security grant, will probably be rescheduled to early next year, said Transit Police Chief Paul MacMillan, whose agency was slated to participate.
He said he anticipates the new training scenario will be similar to the one already planned.
“Why wouldn’t we do it?” MacMillan said. “Just because we had one event doesn’t mean that we might not have another one. And it behooves us to continually work together to investigate these types of incidents.”
Cheryl Fiandaca, spokeswoman for the Boston Police Department, said the agencies had no choice but to postpone this year’s Urban Shield.
“The resources and logistics of putting something of this magnitude together in light of what just happened would be challenging,” she said. “To put together an exercise that would be a really valuable training and teaching tool we need more time.”
Officials from a dozen agencies had been meeting for months to plan the scenario. They behaved much like movie producers, recruiting students from Northeastern University and the Boston Police Academy to play the parts of terrorists and witnesses.
They scouted warehouses and homes around Chelsea and Winthrop that could be used as a terrorist safe house.
‘The main goal of this was to arrest as many of the people as possible and absolutely identify where the [supposed] cache of bombs was being kept.’
Quote Icon
The basic plot was this: Half a dozen members of Free America Citizens wanted to gauge police response to a bomb scare. They would plant hoax devices, then stay on the scene to watch and record the bomb squad and detectives as they responded, as a dry run to a larger attack.
The participating detectives, however, would not have known they were being watched. They would only be told that they were responding to an urgent terrorist threat. The goal of the training was for them to figure out the motives of Free America Citizens as they investigated the case, the official said.
The planned exercise has eerie similarities to the police investigation that led to the capture of the alleged Boston Marathon bombers, Tamerlan and Dzhokhar Tsarnaev, whose images were caught on video cameras and who were captured after a car chase and shoot-out with police.
In the training scenario, investigators participating in Urban Shield would have to track down footage of the bombers caught by street surveillance cameras and the phones of “witnesses.”
They would have to call on intelligence analysts to figure out which terrorist cell might be threatening the city.
In the scenario, the terrorists would flee police in stolen cars they would dump in cities outside Boston, which would compel detectives from different jurisdictions to cooperate and share intelligence.
One major clue would have been the body of one of the terrorists found near a stolen car, dead from a self-inflicted gunshot wound. There were also false leads to keep investigators guessing, the official said.
“We’d have detectives running ragged,” the official said. “The main goal of this was to arrest as many of the people as possible and absolutely identify where the cache of bombs was being kept.”
Fiandaca, the police spokeswoman, declined to say what a new training might look like.
“We can’t talk about what we’re doing for emergency preparedness,” she said. “The people who participate in this don’t know what the scenario is.”
Maria Cramer can be reached at mcramer@globe.com.
Follow her on Twitter @GlobeMCramer.