EMJ CREW LEFT THE ENG RUNNING AFTER PARKING AT THE GATE.

Narrative

ENG RUNNING AFTER PARKED. ARRIVED AT BOS AFTER DELAYS AND WX ON ARR AND APCH. AT GATE PERFORMED PARKING CHKLIST AND L ACFT WITH CREW. OVERHEARD SOMEONE TALKING ABOUT AN ENG RUNNING ON A PARKED ACFT; WHICH TURNED OUT TO BE OURS. POSSIBLY BUMPED THRUST LEVER DURING SHUTDOWN PROC AND FOR SOME UNKNOWN REASON DID NOT LOOK AT EICAS ENG INSTS AS I ALWAYS DO. UPON REFLECTION; PICKED THE WRONG FLT TO STOP DOING GOOD HABITS. CONTRIBUTING FACTORS: POURING RAIN AND ACFT PARKED NEXT TO US WITH APU AND ENG RUNNING MASKED SOUND OF ENG. ALSO; FATIGUE OF PREVIOUS DAY WITH LOUSY NIGHT SLEEP. REGARDLESS; WAS SURPRISED TO FIND MYSELF IN THIS SIT AND WILL NOT LET IT HAPPEN AGAIN. SOMEWHERE DURING THE SHUTDOWN/PARKING PROC THERE WAS A DISTR THAT WAS A COMBINATION OF ALL THESE FACTORS COMBINED THAT CAUSED US TO MISS SOMETHING SIMPLE; BUT THE CHAIN WASN'T BROKEN. SUPPLEMENTAL INFO FROM ACN 631227: AFTER WE ARRIVED INTO BOS AND COMPLETED THE CHKLIST. NEXT CREW WHO WERE WAITING FOR THE ACFT TOOK OVER THE AIRPLANE. AFTER ABOUT 5 MINS. OPS INFORMED US ONE OF THE ENGS WERE RUNNING WHEN THE CREW TOOK OVER THE ACFT. ALTHOUGH THE CAPT AND I WERE SURE THAT WE DID THE CHKLIST IN ITS ENTIRETY; WE THINK THAT THE THRUST WASN'T IDLE WHEN THRUST WAS SELECTED TO IDLE; THEREFORE; THE ENG DIDN'T STOP. NEVERTHELESS; WE SHOULD HAVE CAUGHT IT BY CONFIRMING THE SHUTDOWN ON EICAS. ALTHOUGH EMB MANUAL DOESN'T STATE THAT FO HAS TO CONFIRM THE ENG SHUT DOWN DURING PARKING CHK; I FEEL RESPONSIBLE ABOUT IT.