As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2004 - BWI - FLIGHT CREW REPORTED LAV SMOKE INDICATION AFTER TAKEOFF, NO ACTUAL FIRE OR SMOKE PRESENT. EWR MX REMOVED AND REPLACED LAV SMOKE DETECTOR AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. ACFT WAS APPROVED TO RETURN TO SERVICE.