Bridgeport — Bruce W. Browne, the estranged half-brother of a former U.S. senator, wanted to impress his fiancée during an outing in Old Lyme last summer, so he commandeered a boat and pretended he was a U.S. Coast Guard agent.

Browne pulled over a Jet-ski driver and ordered him to return to the dock because he did not have a boating license, according to testimony Monday in U.S. District Court.

In March 2013, Browne volunteered to help a woman he knew dissuade her teenage sons from using marijuana, so he impersonated a federal agent and went to the family home, wielding a gun and putting one boy in handcuffs during a so-called "scared straight" intervention.

Browne, 47, of Wolcott, admitted to those crimes Monday in U.S. District Court in Bridgeport, where he waived indictment and pleaded guilty to two counts of impersonating a federal officer.

He also pleaded guilty to altering his 2002 discharge form from the U.S. Coast Guard reserve when he applied for a Connecticut pistol permit in February 2013. He had been discharged "under other than honorable conditions," according to U.S. Attorney Ray Miller, but Browne obliterated the words "under other than" when submitting the discharge form to state authorities.

He is now a convicted felon facing up to 18 months in prison, a fine of up to $30,000 and a year of supervised release when he is sentenced by U.S. District Judge Stefan R. Underhill on May 19. Browne was released on a $200,000 bond, ordered to undergo a mental health evaluation and to have no contact with the victims or witnesses of his crimes.

Browne is the half-brother of former U.S. Sen. Scott Brown of Massachusetts, although they spell their last names differently. Scott Brown has said they are not close. Browne owns a security company, Northeast Surveillance & Communications, and will be permitted to travel along the East Coast for business while awaiting sentencing.

Browne had initially been charged by Old Lyme and state police following the Aug. 8 incident in Old Lyme, but federal authorities, including agents from the U.S. Coast Guard and Department of Homeland Security, undertook an investigation due to the nature of the charges. The state charges are still pending.

In the Old Lyme incident, Browne initially told local police he was a Coast Guard agent, then admitted he was trying to impress his fiancée, according to Miller, the U.S. attorney. The police searched Browne's car, a Ford Crown Victoria outfitted as a police vehicle, and seized numerous law enforcement items, including a bulletproof/tactical vest with police insignia and a Transportation Security Administration badge, multiple sets of handcuffs, three handguns, loaded gun magazines, significant quantities of ammunition including hollow point bullets, a knife, and a police tactical baton.

Released on bond, Browne threw four other law enforcement badges in his possession into the Chestnut Hill Reservoir in Wolcott. He subsequently informed federal authorities of his actions and, on Sept. 27, 2013, a dive team from the Connecticut State Police recovered the badges.

During Monday's court proceeding, Browne, wearing a white dress shirt, sat between defense attorneys Richard Cramer and William Gerace and quietly answered a series of questions posed by the judge. Underhill told Browne he would not be able to vote, serve on a jury or own firearms.

"If you pleaded guilty today, you cannot ever have a gun in your house, a gun in your car," the judge said. "You can't be around people who have guns."

Browne said he understood.

Browne was visiting his fiancée's vacation home in the Point O' Woods section of Old Lyme last summer when a resident called police to report a man was walking on Sea View Road wearing a "SWAT-like uniform" and carrying a gun, according to police.

The resident said Browne identified himself as a member of the Coast Guard's security team who was going to take photos of the barque Eagle, which was returning to New London from its summer cruise. The witness wrote down Browne's license plate number, and officers located the car at 32 Sea View Road, where Browne was attending a cookout, police said.

The police learned that Browne's fiancée asked a friend to take Browne out on the friend's boat. As the boat was backing out of the slip, Browne informed the boat owner that "I am commandeering your boat. Your boat is now a U.S. Coast Guard vessel." The boat owner thought Browne was kidding, according to Miller, the federal prosecutor, but he wasn't. At Browne's direction, the boat owner approached two boats operated by private citizens. In each instance, he required the boat operators to produce their boating licenses.

In the "scared straight" incident in March 2013, he offered to help an acquaintance who believed Browne was a federal law enforcement officer with experience in narcotics matters, according to the government. Browne arrived in a Crown Victoria that resembled a police vehicle, displayed a badge and had a holstered gun and handcuffs secured on his belt. He introduced himself to the 15- and 17-year-olds as "Agent Brice" and "Detective Brice" and escorted them to their rooms while ordering their mother to stay downstairs.

The mother later learned from her son that Browne had drawn his gun and handcuffed her son while searching the room. Eventually, Browne walked downstairs with one of the minors and entered the garage, pointing the unholstered gun in the boy's direction. He returned with a backpack that contained about $200, a small amount of what appeared to be marijuana and a pipe. After confirming with the mother that the money was from a legitimate source, Browne gave her the money and took the backpack and all of its contents. He told the boys he had conducted surveillance on the boys in the prior week and related several incidents to them that seemed to authenticate that claim.

k.florin@theday.com