WORCESTER - About 4½ hours of jury deliberations failed to produce a verdict Monday in the trial of a Worcester man charged with murder in a fatal shooting three years ago at the Upland Gardens apartment complex.

Fathi Jaara, 24, of 15 Fern St. is charged as a joint venturer in the Oct. 2, 2014, shooting death of 19-year-old Christian A. Obeng outside an apartment  building at 8 Upland Gardens Drive.

Prosecutors allege that the killing was gang-related and that Mr. Jaara planned it, even though he was not accused of firing the bullet that struck Mr. Obeng in the back of his head and caused his death.

The seven women and five men of the jury began their deliberations about 11:30 a.m. Monday, after hearing closing arguments by the lawyers and Judge Janet Kenton-Walker's instructions on the law. Judge Kenton-Walker excused the jurors for the night about 4 p.m. and asked them to resume their deliberations at 9 a.m. Tuesday.

There was testimony introduced during the Worcester Superior Court trial that Mr. Jaara, his brother, Ahmad Jaara and Dominic Bonneville, the man prosecutors allege fired the fatal shot, were members of the Providence Street Posse, part of the larger East Side gang. Mr. Obeng and Jose Lora, who was with him when he was gunned down, were members of the rival Kilby Street Posse, according to testimony.

Prosecutors contend that after encountering Mr. Obeng and Mr. Lora at Upland Gardens on the day of the killing, Fathi Jaara called his brother and had him drive Mr. Bonneville to the apartment complex. Mr. Bonneville arrived armed with a .380-caliber handgun and shot Mr. Obeng after he and Mr. Jaara called Mr. Obeng and Mr. Lora out of the apartment they were visiting, the prosecution maintained. Alberto Rodriguez, who was in the apartment with Mr. Obeng and Mr. Lora, suffered a gunshot wound to his shoulder, according to trial testimony.

Mr. Bonneville, who was also charged with Mr. Obeng's murder, was acquitted after a separate trial last December. An accessory charge against Ahmad Jaara was dismissed and prosecutors are appealing the dismissal.

In his closing argument, Mr. Jaara's lawyer, Sean J. Gallagher, said the ballistic evidence in the case showed there was an exchange of gunfire when Mr. Obeng was killed and argued that there was no way of knowing which side fired the first shot.

Mr. Gallagher questioned the credibility of Ricki Tabor, a key prosecution witness in the case, saying Mr. Tabor's testimony was either "a lie" or "unreliable."

Mr. Tabor, who was a close friend of Mr. Obeng and knew Fathi Jaara, testified that he saw Mr. Jaara and a man wearing a gray hooded sweatshirt arguing with Mr. Obeng and Mr. Lora outside 8 Upland Gardens Drive on the evening of the killing. Moments later, he said, he heard gunshots and saw the man clad in the gray sweatshirt waving a handgun back and forth in front of him. Mr. Tabor identified the gunman as Mr. Bonneville from a photo array shown to him by police.

Mr. Gallagher said Mr. Tabor initially placed the time of the shooting at about 2:45 p.m. and later said it was sometime after 5:30 p.m.

"Do you think he was there at all?" Mr. Gallagher asked. Even if Mr. Tabor were to be believed, his testimony had Mr. Jaara involved in an argument prior to the shooting, "nothing else," according to Mr. Gallagher.

"You have to have the intent, the mindset of a murderer, to commit murder," the defense lawyer argued.

Although there was evidence of 25 calls among cellphones associated with the Jaara brothers and Mr. Bonneville just prior to the shooting, there was no evidence of what was said by anyone during those calls, Mr. Gallagher told the jurors.

Assistant District Attorney Brett F. Dillon asked the jurors to use their "common sense" in determining what was said during the calls and described them as the beginning of Mr. Jaara's "plan to kill."

The prosecutor said the evidence showed Mr. Jaara knowingly participated with Mr. Bonneville in causing the death of Mr. Obeng, a rival gang member who had crossed into Providence Street Posse territory.

"They chose to kill Christian Obeng," Mr. Dillon told the jurors. He said it was clear from the evidence that Mr. Bonneville shot first and asked the jury to reject the defense's suggestion that Mr. Bonneville may have acted in defense of himself or Mr. Jaara.