Montemarano contends that the police targeted his client based on "no more than the belief that 'these guys are bad.'"

Prosecutors say the men were looking for a "big score" ahead of Christmas.

Law enforcement can determine the amount of prison time the targets will face by increasing or decreasing the volume of drugs said to be at stake. Encouraging the use of guns can also beef up potential sentences.

For two of the defendants in the hotel case, the government has said it will seek mandatory minimum sentences of 20 years, based on the combination of 5 kilograms of cocaine and their prior felony convictions.

In cases elsewhere, lawyers have successfully argued that inflating the story to manipulate sentences amounts to a form of entrapment. While not enough to get an acquittal, the argument has sometimes resulted in lesser sentences.

Zayas, the ATF agent, testified in a recent Maryland case that investigators concoct their stories in such a way that the robbery appears difficult and potentially dangerous.

"What we do is by raising that level of violence, we then weed out individuals that aren't truly involved in this type of crime, which has happened to us in the past," Zayas said. "We have had individuals walk away from the scenario."

Marcinko said carrying out the robbery is not needed to prove the conspiracy.

"We're not inventing a crime. This type of activity is coming our way through human sources, through intelligence," he said. "We don't plant the seed."

Drug-related robberies are rarely reported to police because the victims are also involved in crimes. But Rosenstein said they can lead to other crimes as the violence spills over.

That makes it more important for authorities to bring in those responsible, he said.

"Home-invasion robberies are responsible for a significant amount of murders and shootings in the city," Rosenstein said. "You most often hear about it when there's some innocent bystander shot."

Added Steven Pugmire, a senior agent with the ATF in Baltimore: "If we can use a tool available to us that is perfectly legal and it targets the worst of the worst people and it takes them off the street for a significant amount of time, we're going to do that."