A Manhattan judge declared a mistrial yesterday in the manslaughter trial of an undercover policeman who shot unarmed African art restorer Ousmane Zongo in a storage warehouse two years ago.

State Supreme Court Justice Daniel FitzGerald ended the trial after jurors sent their second note saying they were unable to decide unanimously the guilt or innocence of Officer Bryan Conroy in Zongo’s death. They had sent the first note late Friday.

“We have thoroughly examined the facts and charges, and no further deliberations will resolve our differences,” the jurors’ second note said.

Officer Conroy was charged with second-degree manslaughter for fatally shooting Zongo on May 22, 2003, inside Chelsea Mini-Storage on West 27th Street. Officer Conroy, 25, would have faced up to 15 years in prison if convicted.

Officer Conroy’s lawyer, Stuart London, said he and prosecutors met with jurors for about 35 minutes after Judge FitzGerald declared the mistrial. He said jurors told them “it all came down to justification,” whether Officer Conroy was justified in shooting when he did.

Mr. London said it was unfortunate the jury did not reach a unanimous decision but it was clear that the prosecution did not prove its case beyond a reasonable doubt. He refused to divulge publicly what the jurors reported as their final vote.

The Manhattan district attorney’s office will retry the case, spokeswoman Barbara Thompson said.

The judge ordered all the parties back to court on April 7 for motions and discussion of the likely retrial.

The president of the Patrolmen’s Benevolent Association, Patrick Lynch, turned aside a question about whether the defense won.

“There are no winners or losers in this,” he said. “This police officer had to do what no police officer wants to do.”

The courtroom was crowded with police officers in civilian clothes, behind the defense table, and supporters of the Zongo family, behind the prosecution table. There was little audience reaction when the judge declared the mistrial and dismissed the jury.

Zongo’s wife, Salimata Sanfo, said later through an interpreter that she has confidence in God and the jury system and believes truth and justice will be served soon.

Ms. Sanfo said she has no ill feelings toward police in general – only against Officer Conroy, because “he is a killer.”