testified that in a response to a radiogram he arrested the defendant coming out of a currency exchange. The defendant was then brought to the police station where he was identified by Miss Murphy the next day in a lineup. James Cusack, a detective, testified that on the evening of July 27, 1962, he had a conversation with the defendant. The detective showed the *206 defendant the case report on the Leader Cleaner robbery which according to the description given the police by Miss Murphy identified the defendant. When Detective Cusack indicated to the defendant that he had been a fool to show his right hand at the time of the robbery since the first joint of his right thumb was missing, the defendant, according to Cusack, admitted,"You got me, I know you got me."
[1] The defendant testified that he had not committed the crime charged. He claimed that he had never spoken with Detective Cusack and had not indicated his guilt as Cusack testified. The defendant said that at the time of the robbery he was engaged in promotional work for Mr. William Jack of Jack's Drive-In Lounge but that he did not have any particular hours. The defendant on cross  examination admitted that he wrote Miss Murphy a letter which stated that he was not working the day of the robbery and that he was missing "the first two digits" from his right thumb. After the defense rested, the People in rebuttal, introduced (to affect the defendant's credibility) an exhibit, stipulated to