On Aug. 7, police boarded a boat Delegate Jon Cardin and his fiancee were on with friends in the Inner Harbor and pretended to search for contraband until Cardin popped the question. A police helicopter flew overhead.

Police spokesman Anthony Guglielmi said Friday that an internal investigation into the event found that the sergeant, who was not identified, “improperly exercised his discretion” in the incident. He said the matter must go to a police trial board.

Cardin reimbursed police $300 for the incident, gave $1,000 to the department’s mounted unit and has repeatedly apologized.