As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB SMOKE WAS EVIDENT IN THE CABIN AND COCKPIT. THE PILOTS TURNED AIRCRAFT AND RETURNED TO BASE, AND LANDED WITHOUT INCIDENT. TROUBLESHOOTING REVEALED THE #1 SCUPPER DRAIN SEAL FAILED ALLOWING OIL INTO THE #1 ENGINE BLEED AIR SYSTEM THAT IS USED FOR CABIN AND COCKPIT HEATING AMONG OTHER FUNCTIONS AS WELL.