Last year I sat on a criminal case for 2 weeks for jury duty in NY City. The charge was operation of a motor vehicle while intoxicated. The defendant was acquitted, but during the trial something came up where the defendant did not admit at first to a drug trafficking charge but then suddenly admitted it. Because of that we went to lunch, then everything resumed normally and we never heard about it again

So what I ask is don't they fingerprint defendants upon arrest so their rap sheet comes up both from NY and other states (FBI check) so that whether they admit to a criminal history is of no importance?

What difference would it make if the defendant admitted to it or not, such a record would always show up when arrested, no?

Because often previous arrests that may have had nothing to do with the current case is not admissible evidence.

I'm sure the police and prosecutor were aware of the defendant's past record. But it was immaterial to the DUI, especially if were only a charge and not a conviction.

Not sure how the info came out in court, but if the judge called a recess immediately afterward, it may be because the testimony should not have been allowed. I'm a bit surprised you weren't admonished to ignore the testimony.

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so what I ask is don't they fingerprint defendants upon arrest so their rap sheet comes up both from NY and other states (FBI check) so that whether or not they admit to a criminal history is of no importance?

what difference would it make if the defendant admitted to it or not, such a record would always show up when arrested, no?

If the defendant had been arrested on a drug charge once upon a time, that doesn't mean that he or she had been convicted. So such fingerprint evidence, rap sheet, etc. may have been there but, as ScottGem has told you, it probably wasn't relevant to the trial at which you were on the jury, and so it was excluded.