The Department of Justice has opened a criminal investigation into the door plug blowout on a Boeing 737 Max 9 plane during an Alaska Airlines flight in January, The Wall Street Journal reported Saturday.The Wall Street Journal, citing “documents and people familiar with the matter,” reported that the DOJ has contacted some passengers who were on the flight to notify them that they are potential victims in the criminal investigation, and that the agency has interviewed pilots and flight attendants who were on the flight.Both the Justice Department and Boeing said they had no comment on…