Cheye Calvo and his wife, Trinity Tomsic, have two new dogs but can't forget what happened. Photograph by Stephen Voss

What happened at Calvo's home on the evening of July 29, 2008, was well covered by national media: After walking his dogs, he brought in a package addressed to his wife, Trinity Tomsic, thinking it was a shipment of gardening supplies. He was wrong. The package contained 32 pounds of marijuana that had been intercepted by police and then delivered to his home.

Calvo was upstairs when he heard his mother-in-law, Georgia Porter, scream. The Prince George's Sheriff's Office SWAT team had burst through the front door and killed both dogs. Tomsic came home to find Calvo and Porter handcuffed, pleading their innocence.

About a week later, then-sheriff Michael A. Jackson and then-police chief Melvin C. High—now the sheriff—held a press conference in which they said that a FedEx driver had been delivering large quantities of marijuana—totaling 417 pounds—to unsuspecting recipients so an accomplice could retrieve it before the addressees arrived home. High was nevertheless reluctant to clear Calvo and Tomsic from any wrongdoing, and both departments continued to defend their officers' actions.

As traumatic as Calvo's experience was, what happened to Salvatore Culosi was much worse. On January 24, 2006, Culosi went outside to pay a friend—undercover detective David Baucom—money he owed for a sports bet. Since meeting Culosi in October 2005, Baucom had encouraged him to increase what had begun as friendly wagers on sporting events to larger bets. When Culosi wagered $1,500 and lost, Baucom said he'd come by to collect his winnings.

Little did Culosi know that Baucom had called in the Fairfax SWAT team to have him arrested for running a gambling ring. It was during this surprise initiative—in which SWAT officers arrived in military-style gear—that officer Deval Bullock says his finger slipped on the trigger. The bullet tore through Culosi's chest, killing him.

By the time the parents' case was due to be heard on January 18, there was only one remaining defendant, Bullock, because US District judge Leonie M. Brinkema had dismissed the suit against the county, police chief David Rohrer, and Lieutenant James Kellam, head of the SWAT team. The family filed a motion to reconsider with Brinkema and appealed to the Fourth US Circuit Court of Appeals in an effort to get those defendants reinstated. After both efforts failed, the Culosis agreed to a settlement with the county in January.

Neither Maryland nor Virginia has a state law governing the use of SWAT teams, so each jurisdiction is left to do as it sees fit. There is also no DC or federal law governing the District's SWAT deployments.

In Maryland, SWAT teams were deployed 1,618 times between July 1, 2009, and June 30, 2010. Twenty-three percent of the deployments, or 373, were in Prince George's County, including 200 for nonviolent crimes. In the same period, Montgomery County had two deployments for nonviolent crimes, Howard County had 28, and Anne Arundel had 53.

No such statewide statistics are available in Virginia. However, Fairfax County Police spokesperson Mary Ann Jennings says Fairfax had 105 deployments for that same period. After repeated requests, neither Arlington nor Alexandria provided its data. According to Lieutenant Robert Glover of the Special Operations Division, the District's police department had 76 deployments; of those, none were for nonviolent crimes.

Comparisons among jurisdictions can be tricky. Like Prince George's County, Baltimore City has lots of drug-related crime and yet doesn't use SWAT teams nearly as often—the city had only 64 deployments for nonviolent crimes in that same period.

But that may be an unfair comparison, says Baltimore police spokesman Anthony Guglielmi: "We have a dedicated unit that does drugs and violent crime—that's all they do. Our guys are specially trained in drugs because it's Baltimore."

Still, when sending a SWAT team is an option, Guglielmi says, his department always uses a risk assessment to determine whether a SWAT team is an appropriate use of force—something Prince George's doesn't do. Guglielmi was reluctant to go into the specifics of the checklist—it's not something he wants would-be criminals to know—but he says it takes into consideration whether a suspect has a criminal background, whether he or she has weapons, and whether the incident poses a threat to the public.

Montgomery County follows a similar procedure, says Captain Darryl W. McSwain, director of the police department's Special Operations Division. All of the county's search warrants are reviewed by an executive officer, and if a SWAT team is being considered, the SWAT sergeant or Special Operations Division deputy director looks for details—the location of the incident, whether the suspect has a violent history, gang affiliations, prior arrests, firearms—that may indicate the need for a SWAT team. Low-risk warrants are served by detectives and patrol officers who aren't as heavily armed.

In a case like Calvo's—in which drugs were sent to an address whose residents had no criminal background or registered weapons—McSwain says the use of a SWAT team wouldn't be automatic: "Unless there is a reason to believe that the warrant service would be high risk, we would not automatically assume the risk."

According to Prince George's police spokesperson Captain Mistinette Mints, prior to the Calvo case the county issued all of its search warrants—regardless of the details of the case—by sending a SWAT team outfitted with shields, helmets, and a battering ram.