Prosecutors put their star witness — a convicted gun and drug dealer --on the stand Thursday to testify in the trial of a Prince George’s County police officer accused of gun theft and misconduct.

Troy Hammond, 35, told jurors that he bought his weapons from a man called “Pooh-Pooh,” who himself got the guns from “Cool.” The three friends who had worked together at a telecommunications company were participants in the seedy underworld of firearms trading, using aliases and exchanging cash for guns on the street, Hammond testified.

Problem was, prosecutors say, “Cool” was actually Juan Carter, a county police officer assigned to a state police-run task force specifically meant to take guns off the street. Carter was instead swiping many of the weapons he seized and distributing them to his criminal associates, prosecutors say.

On the second day of Carter’s trial in Prince George’s County Circuit Court in Upper Marlboro, prosecutors sought to connect the officer with the nefarious activity he swore to stop. Hammond, a 35-year-old told jurors he ended up selling two weapons that he got, in a roundabout way, from Carter to an ATF informant.

Hammond testified that he and Carter, whose nickname was “Cool,” had known each another from previous work together at Vital communications and that they would sometimes hang out and drink. In December 2008, Hammond testified, he arranged to buy five guns from a third friend and co-worker, Delmar Tyrone Thompson, who was known on the street as “Pooh-Pooh.” Thompson, he said, had gotten the weapons from Carter.

Hammond testified that he unknowingly sold two of the weapons the next month to an ATF informant. He was eventually charged and convicted in that case and is serving a prison sentence. He said that he discarded another weapon in the woods and intended to get rid of two others, two of which he buried on his uncle’s property in Cape St. Claire. He said that Carter told him that “if I still had ’em, get rid of ’em.”

Whether or not jurors believe Hammond might prove pivotal in the case against Carter, who prosecutors say seized more than 20 guns that never made it to the Prince George’s police property room as they should have. Defense attorneys argue that Carter was not selling or giving away the weapons but was instead being made the “fall guy” for a task force beset by poor record-keeping and other, systemic problems.

The trial is Carter’s second on the same offenses after one last year ended with a hung jury.

In their questioning, defense attorneys sought to dismantle Hammond’s credibility and confuse his story. They highlighted his drug convictions and confronted him with previous testimony that seemed to contradict what he was telling the jury on Thursday.

Hammond, who came into court in shackles and slumped his shoulders throughout the proceedings, spoke in a near whisper and rarely looked up, prompting a prosecutor at one point to reposition a microphone to his mouth so jurors could hear. He appeared confused, and testimony wandered. He could not remember specific dates, and his account of how many guns he bought and what happened to them was somewhat unclear.

Carter’s trial is expected to last into next week.