A state report released Friday called the overall emergency response to the Boston Marathon bombings a "great success," but revealed that some police officers fired recklessly in the Watertown shootout with the suspects, and that officers were deployed chaotically in the ensuing manhunt.
Eventually, more than 2,500 officers from New England and New York arrived in Watertown, many without orders to do so, the report said.
The first officers who confronted the Marathon bombers acted appropriately, the 130-page report said, but a swarm of police who followed often failed to identify their targets before firing. The cascade of gunshots created dangerous crossfire during two intense encounters, according to the study.
More than 200 shots were fired during the shootout shortly after midnight on April 19, 2013. Tamerlan Tsarnaev, one of the bombers, was killed when his brother, Dzhokhar, struck him in a stolen SUV while fleeing from the gunfire. Dzhokhar Tsarnaev later escaped on foot into a Watertown backyard.
"Weapons discipline was lacking by the multitude of law enforcement officers in the field during both the firefight with the two suspects near Dexter and Laurel streets, and the standoff with the second suspect who was hiding in a winterized boat in a residential back yard," the report said.
The report noted that when Dzhokhar Tsarnaev escaped the firefight, the authorities pursuing him were delayed by police vehicles parked in the roadway.
An ambulance transporting Transit Police Officer Richard Donohue Jr., who had been critically wounded in the shootout, also was hindered in its effort to reach nearby Mount Auburn Hospital in Cambridge. The report did not address the question of who fired the shot that nearly killed Donohue.
In all, officers from 116 federal, state, and local agencies arrived at the staging area at the Arsenal Mall in Watertown later that day. Many rushed to the shootout scene without orders to do so, or to other locations where the crackle of radio communications had reported suspicious activity.
"There was no command or management structure formally assigned to manage incoming mutual-aid personnel," the report said. "Officers were not assigned roles within the operation or provided briefings on the situation or command structure. This caused logistical issues, command and control issues, and officer safety issues."
After the shootout, an unmarked State Police pickup truck, which mistakenly had been reported stolen, was fired on by an unidentified police officer, the report said. A plainclothes state trooper and Boston police officer in the truck were not injured.
Later, when Dzhokhar Tsarnaev was cornered in a boat in a Watertown backyard, a burst of "contagious" shooting erupted from police who had converged there, the report said.
"An officer fired his weapon without appropriate authority in response to perceived movement in the boat, in turn causing many officers to fire at the boat in the belief that they were being shot at by the suspect," the report said.
Again, dangerous crossfire occurred.
Boston Police Commissioner William Evans, who was named to the city's top police job several months after the bombings, said Friday that he was in command at the scene.
"We had good control over that scene until someone fired. In a situation like that, once one fired, it's sort of a chain reaction," said Evans, who added that "once one fires, they all think they're justified in firing . . . It's not their fault, honestly."
The report said that within moments after Tsarnaev had been discovered in the boat, "more than 100 officers had gathered in front of and behind the home." Many of them raced to the scene on their own after overhearing radio traffic about Tsarnaev's location, the report said.
Once that happened, Evans said, the lines of command blurred as federal, state, and local police poured into the area. None of his officers fired a bullet, Evans said, but others soon started firing even as he yelled into the radio for a cease-fire.
Edward F. Davis, who was Boston police commissioner at the time of the bombings, said the response by authorities saved lives and contained a highly volatile situation over several days. But he also acknowledged that law-enforcement officers had fired their weapons too often in Watertown.
"Clearly, the number of rounds that were fired were problematic. But you find that as a very common problem in any kind of a military situation," Davis said Friday. "Firearms discipline is something that we need to improve our training on. There's no question about that."
Davis said reports such as the one released Friday are helpful, but that "when you go back after the action and you're slowly picking apart everything that happened, it's easy to point to inefficient and kind of inappropriate use of things."
Firefights, he said, are chaotic by nature.
"The truth of the matter is that officers under fire are doing the best they can under a bad situation," Davis said. "Regardless of what this report says, these officers who responded to these scenes acted heroically and above and beyond the call of duty."
Despite the confusion in Watertown, the report praised the coordination among law-enforcement agencies and the relatively quick identification of the bombers.
"Throughout the week, police agencies worked together incredibly well, coordinating resources, assets, and sharing information." the report said.
The bombings killed three people and injured more than 260. Three days later, on the night of April 18, the Tsarnaevs allegedly killed MIT Police Officer Sean Collier in Cambridge. Two hours after that murder — at 12:41 a.m., April 19 — the shootout erupted in Watertown.
The report also praised the medical system, organized under the leadership of the Boston Athletic Association, which ensured that police and emergency workers could quickly treat and transport the injured in the bombings. All of the 60 critically injured patients taken to hospitals survived.
Comprehensive mental health and human services were provided to anyone affected, the report said.
The report also said the reopening of Boylston Street after the explosions was "extremely organized," a testament to strong planning by the city of Boston. That planning has been fortified in the last two years with lessons learned from the bombings, Boston Mayor Martin J. Walsh said.
Rene Fielding, director of the city's Office of Emergency Management, said Boston now operates an emergency command center on Marathon Day. In 2013, the city activated a command center only after the bombings occurred.
Planning also is in place to aid and inform thousands of runners who might be stopped on the course by a major disruption, Fielding said. In 2013, there was no organized strategy.
Dzhokhar Tsarnaev is on trial in US District Court in Boston on 30 charges, including 17 that could bring the death penalty, for carrying out the attacks. Closing arguments in the first phase of the trial, in which the jury will decide whether he is guilty, are scheduled for Monday.
Tsarnaev's lawyers have already stated that he and his brother set off the bombs. But in the second phase of the trial, when a penalty will be determined, they will try to persuade jurors to sentence Tsarnaev to a life sentence instead of death.
The report originally was scheduled to be released in 2014, but it was held back to conduct more work. However, some of its findings were shared with various agencies at that time.
A Massachusetts Emergency Management Agency spokesman said last month that officials would release it only after this year's Marathon, which is on April 20, because the agency did not want to detract from the race.
The Globe filed a public records request for the report on March 16 and, after that was ignored, appealed March 27 to the governor's office and the office of Secretary of State William F. Galvin, which enforces the public records law.
Evans, the Boston police commissioner, said he welcomed the report but that the department already had studied its response to the bombings.
"We're in the profession a long time. We didn't need this report to tell us. We always self-examine our practices," he said. "It was a great effort by everyone. We aren't perfect. We learned from our mistakes."
State Police spokesman David Procopio also said his agency had already adopted many of the recommendations in the report.
Thomas Grilk, executive director of the Boston Athletic Association, said the study has resulted in improvements.
"Public safety and security last year were increased significantly, and it appeared to be done in a way that was not obtrusive," Grilk said. "From what I could see, there was a splendid balance of security and maintaining the nature and character of a day of celebration."
The study, which cost $419,252, was chaired by the Massachusetts Emergency Management Agency, working with the Massachusetts State Police, the MBTA Transit Police, the state Department of Public Health, the Massachusetts National Guard, and officials from Boston, Cambridge and Watertown.
Martin Finucane and Todd Wallack of the Globe staff and Globe correspondent Jeremy C. Fox contributed to his report. Brian MacQuarrie can be reached at email@example.com. Maria Sacchetti at firstname.lastname@example.org.