A 29-year-old man was arrested for allegedly having an open container of alcohol while taking pictures Sunday afternoon in front of the Boston home of U.S. Secretary of State John Kerry.

The suspicious activity was spotted by Kerry’s security staff. The secretary of state wasn't home at the time of the incident.

"Members of the State Department Diplomatic Security Service observed a man taking a picture of a window in the Secretary's Boston home," Kerry spokesman Glen Johnson said in a statement, adding that a pellet gun was found in the man’s car, which was idling in a no-parking zone.

Kerry, who served 28 years in the U.S. Senate before being tapped as President Barack Obama’s secretary of state, was visiting his wife, Teresa Heinz Kerry, at Spaulding Rehabilitation Hospital in Boston on Sunday. Heinz Kerry is being treated there as she recovers from a seizure suffered last week. Doctors are still unsure what caused the seizure, but ruled out a heart attack, stroke or brain tumor, according to the Boston Globe. Her condition had been upgraded from "fair" to "good."

A spokeswoman for the Boston Police Department told the Associated Press that the man, identified as Vladimir Romanov, of Boston, said he was taking pictures of Kerry’s house on Beacon Hill for a friend, but then deleted the photos. The man was taking the pictures from his car, and police noticed he had an open container of alcohol in the vehicle.

The suspect was scheduled to be appear in court on Monday on charges of having an open container of alcohol.

Kerry, who unsuccessfully ran for president on the 2004 Democratic ticket, has a net worth pegged at $194 million.

His five-story, 8,286-square-foot Beacon Hill home is valued at about $7 million, according to the Globe. The manse features an elevator, six fireplaces, five bedrooms and six bathrooms.