— Appeal by defendant from a judgment of the Supreme Court, Kings County (Bernstein, J.), rendered May 16, 1979, convicting him of robbery in the second degree (two counts), robbery in the third degree, criminal possession of stolen property in the first degree and criminal possession of a weapon in the third degree, upon a jury verdict, and imposing sentence. Judgment modified, on the law, by reversing the convictions and sentences for robbery in the second degree (two counts), robbery in the third degree and criminal possession of stolen property in the first degree and new trial ordered as to said counts. As so modified, judgment affirmed. It was improper for the prosecutor to question the defendant about aliases used in connection with arrests made where those arrests were not subject to cross-examination under a Sandoval ruling. The prosecutor elicited information which alerted the jury to criminal involvement by the defendant which was excluded by the ruling (People v Sellars, 74 AD2d 551). This error cannot be deemed harmless in view of the less than overwhelming proof of guilt, and the importance of the witnesses’ credibility in reaching a verdict. Therefore, a new trial is required. However, the conviction of criminal possession of a weapon in the third degree must be affirmed since, at trial, defendant admitted having possessed the weapon. Mangano, J. P., Gulotta, O’Connor and Bracken, JJ., concur.