Thirty-one federal and local law enforcement officers were honored Tuesday for their efforts in putting together cases that helped put gun offenders, armed robbers, and other criminals behind bars at a ceremony led by Maryland U.S. Attorney Rod J. Rosenstein.

Inside the jurors’ lounge at the U.S. District Courthouse in Greenbelt, Rosenstein was joined by other area law enforcement officials in recognizing the federal agents and police officers for their work.

“We intend to send a powerful message that gun crime means jail time,” Rosenstein said.

Three of the officers — Sgt. Leslie Thomas of the D.C. police department and Sgts. Sean Chaney and Dave Blazer of the Prince George’s County police — worked on joint federal-local task forces targeting illegal guns and violent offenders.

Some of the nearly two dozen local police officers who were honored were recognized for their efforts building cases in the normal course of their work, which were prosecuted federally instead of at the state level.

Officials sometimes prosecute defendants federally because the federal criminal justice system has stiffer penalties for some offenses. In 2006, federal, state, and local law enforcement officials launched a program, EXILE, in which defendants are charged in federal court with gun crimes and other offenses.

Cpl. Steven R. Cobb, a detective with the Prince George’s police, built a case against a man who committed a seris of robberies in late 2008 and early 2009. The defendant pleaded guilty in federal court to a series of robberies and was sentenced to more than nine years in prison, Rosenstein said.

Five Montgomery County police officers were recognized for arresting a violent gun offender.

Katharine Benedict and John Cooney, special agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives, were honored for their work preparing cases against violent gun offenders. Rosenstein said ATF agents compile detailed cases against gun suspects, which are put together with blue covers. “You know when you get a blue cover the case is ready to go,” Rosenstein said.

“Our partnership with federal law enforcement is paramount when it comes to protecting the people of Prince George’s County against violent crime,” said State’s Attorney Angela D. Alsobrooks, who attended the ceremony along with county police Chief Mark Magaw.