That raid — and its outcome — mirrored a 2005 Baltimore County police action, in which officers equipped with a battering ram and flash grenades stormed into a Dundalk home to search for drugs. In an upstairs bedroom, a 44-year-old woman pointed a revolver at Artson and he fired three rounds, killing her.
Although deaths mark a small percentage of the more than 1,600 tactical deployments conducted each year in Maryland, critics say that such raids have become too common and that the units should receive greater public scrutiny.
"SWAT teams are very traumatic. It's not the same thing as having an officer come to your door," said Berwyn Heights Mayor Cheye Calvo, the target of a misguided raid in July 2008.
Sheriff's deputies burst into his home with automatic weapons, handcuffing him and fatally shooting his two dogs. A review of the raid found that police targeted Calvo's home after drug dealers sent a package of marijuana to him and other unsuspecting homeowners; the dealers hoped to collect the packages before the homeowners did.
Calvo was cleared of any wrongdoing, and a lawsuit against Prince George's County was settled for an undisclosed amount.
That highly publicized incident prompted state legislators to require police departments to submit data every six months on tactical deployments, starting in 2010. But Calvo and others say the data is not thoroughly analyzed, so it's difficult to determine patterns and problems. Calvo notes, for example, that Howard County reported a 72 percent increase in the use of tactical units from calendar year 2010 to 2011, though the increase is not apparent in the state compilation, which is based on a fiscal year.
Police officials say such deployments provide the safest option, especially when dealing with potentially armed and dangerous suspects.
"In general, tactical units are used for high-risk warrant services," said Cpl. Cathy Batton, a Baltimore County police spokeswoman. She would not comment on the Reisterstown raid, saying the warrant was sealed. She said, "It's not just officer safety, it's the safety of everyone involved," adding that officers get highly specialized training to handle potentially volatile situations.
Capt. John McKissick, commander of the Special Operations Bureau in Howard, said, "These numbers tend to fluctuate," so it is difficult to draw conclusions from only two years of data. He added that the county has reported fewer deployments for the first six months of 2012 than in the same period last year.
Tactical units frequently force their way into homes, sometimes without announcing their presence. The teams were created to handle particularly dangerous situations, such as serving warrants on violent offenders or drug gangs, and dealing with hostage or barricade incidents. Many carry high-powered rifles, and they typically are outfitted with bullet-resistant vests, helmets and shields.
According to the most recent report from the Governor's Office of Crime Control and Prevention, total deployments rose marginally, from 1,618 to 1,641, from fiscal 2010 to 2011. The Prince George's County Police Department had the most, with 343 deployments, followed by Baltimore City with 289, Montgomery County with 139, and Baltimore County with 120.
In each of the two years that the reports have been issued, deployments resulted in a civilian death and more than a dozen injuries. A handful of animals were killed or injured as well.
"On the face of it, with that many involvements from the SWAT Teams, while nobody wants to take a life at all, that doesn't seem like an alarming number [of fatalities] considering the type of people that they're dealing with," said L. Douglas Ward, director of the Division of Public Safety Leadership within the Johns Hopkins University School of Education.
He urged further study, however, to find out "what's behind the numbers," including whether the injured were on the attack when they were hurt, or simply innocent bystanders.
"Statistics are a good tool to get you to ask more questions; they're not going to tell you the whole story," Ward said. Tactical team raids "serve a good purpose, but like anything else, they have to be [based] on good policies and good training, and I think people in general have a right to know if they're being used safely and properly."
The governor's office, which receives the annual report, agrees the data alone don't say much.
"We can't draw conclusions about whether a deployment was necessary or reasonable: Those details are just not reported, the incident-based details," said Raquel Guillory, a spokeswoman for Gov. Martin O'Malley.