As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXTREMELY LOUD HIGH PITCH NOISE IN VICINITY OF L2, L4 & L5 BETWEEN 2.4 -4.0 CABIN DIF PRESSURE CHECKED & INSPECTED BOTH NR 2 WINDOW, FOUND PRESSURE SEALS CONTAMINATED WITH DIRT & DUST PARTICALS ON LOWER EDGE. CLEANED SEALS & MATING SURFACE ON AIRFRAME. PRESSURIZED CABIN TO 6.0 DIFF PRESSURE TWICE WITH NO SQUEALING SOUND. ACFT RETURN BACK IN SERVICE.