Boston's police commissioner says his son was arrested on a charge of operating under the influence in New Hampshire and will seek professional help.

Commissioner Ed Davis wrote on the Police Department's website Monday that his son Phillip informed him he was arrested Friday in Plymouth, N.H., for allegedly operating under the influence.

New Hampshire state police said five passengers in the vehicle ranging in age from 17 to 20 were charged with being a minor in possession of alcohol. They and the 22-year-old Davis are scheduled for arraignment on Feb. 28.

Ed Davis wrote that like many families struggling with substance abuse, his family is reaching out to experts to get his son help.

He said the "sudden and public challenge" is the most difficult issue confronting his family.