Baltimore Police Commissioner Frederick Bealefeld told reporters Tuesday that Delegate Jon Cardin also offered to pay expenses from the incident.
The department is investigating. Officials don't know yet how much Cardin's proposal cost the department.
Cardin, a Democrat who represents Baltimore County, said on his Web site that he had marine police search the boat he and was girlfriend were on. He says he popped the question during the "fuss" Aug. 7 in Baltimore's Inner Harbor.
The department's helicopter also flew overhead.
Cardin says he asked his best friend to help plan the proposal.