One of the Brooklyn narcotics cops charged in a scheme to withhold seized drugs and give them to informants was cleared on all counts this afternoon.

Police officer Julio Alvarez was found not guilty of 18 charges, including conspiracy and falsifying business records, after a bench trial in front of Brooklyn Supreme Court Justice John Walsh.

Alvarez, who had faced up to four years in prison, remained mum outside court.

There was no verdict, however, for his co-defendant, Det. Sean Johnstone.

Johnstone’s lawyer asked for a mistrial because a prosecution witness who claimed Johnstone had falsely arrested him, had several sealed arrests that were not disclosed to the defense.

Walsh instead scheduled testimony for Jan. 31 so Johnstone’s lawyer can quiz the witness about his record.