He had found it in an envelope, addressed by the elder Mr. Longestaffe to Messrs. Slow and Bideawhile, and he had himself posted this letter in a pillar-box near to his own house. In the execution of this manoeuvre, circumstances had greatly befriended him. He had become the tenant of Mr. Longestaffe's house, and at the same time had only been the joint tenant of Mr. Longestaffe's study,--so that Mr. Longestaffe's papers were almost in his very hands. To pick a lock was with him an accomplishment long since learned. But his science in that line did not go so far as to enable him to replace the bolt in its receptacle. He had picked a lock, had found the letter prepared by Mr. Bideawhile with its accompanying envelope, and had then already learned enough of the domestic circumstances of the Longestaffe family to feel assured that unless he could assist the expedition of this hitherto uncompleted letter by his own skill, the letter would never reach its intended destination. In all this fortune had in some degree befriended him. The circumstances being as they were it was hardly possible that the forgery should be discovered. Even though the young man were to swear that the signature was not his, even though the old man were to swear that he had left that drawer properly locked with the unsigned letter in it, still there could be no evidence. People might think. 
He had discovered it in an envelope addressed in Mr. Longstaffe's writing to Messrs. Slow and Bideawhile, and he had posted it himself.
At the time, he was the joint tenant of Mr. Longestaffe's study; and he had long since learned to pick a lock, though he could not then relock it. He had picked a lock, and had found the letter prepared by Mr. Bideawhile. Even if the young man were to swear that the signature was not his, and the old man were to swear that he had left that drawer locked, still there could be no evidence. 