As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED PRESSURIZATION PROBLEMS AND A LOUD SQUEALING NOISE ABOVE CAPTAINS HEAD. EMERGENCY DECLARED RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. RE-TORQUED FASTENERS ON PERIMETER OF LEFT UPPER FORWARD WINDOW PLUGS.