As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INITIAL CLIMB, FLIGHT ATTENDANT REPORTED SMOKE IN REAR OF AIRCRAFT ACCOMPANIED BY LEFT AFT LAVATORY SMOKE DETECTOR SOUNDING. FLIGHT WAS RETURNED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AIRCRAFT AND RAN BOTH ENGINES TO TAKEOFF POWER. NO OIL OR SMOKE WAS NOTED.