YOU SAID:

the breifcase was left at the train station once the meeting were done

INTO JAPANESE

会議が終わったら、ブリーフケースは駅に残されました

BACK INTO ENGLISH

After the meeting, the briefcase was left at the station

INTO JAPANESE

会議終了後、ブリーフケースは駅に置いてありました

BACK INTO ENGLISH

After the meeting, the briefcase was left at the station