LOS ANGELES, Calif. — Jurors deadlocked today in the trial of a reputed gang member charged in the 2010 Halloween killing of a 5-year-old South Los Angeles boy who was shot while showing off his Spider-man costume in his backyard.

Superior Court Judge Bob S. Bowers declared a mistrial after the jury’s foreman said the panel was not able to reach a unanimous verdict in Leonard Hall Jr.’s trial.

The foreman told the judge that jurors were deadlocked 9-3 — with the majority in favor of guilt — on a murder charge and two counts of attempted murder.

The murder charge stems from the slaying of Aaron Shannon Jr., who died from a single gunshot wound to the head, while the attempted murder counts involve the boy’s grandfather and uncle, who were injured during the shooting at about 2 p.m. Oct. 31, 2010, in the 1000 block of East 84th Street.

The neighborhood where the boy lived is an active gang area, but his family had no gang ties, police said shortly after the shooting.

Just after the deadlock, the judge denied defense attorney Carol Ojo’s request to reduce Hall’s $4 million bail.

Outside court, Ojo said of the jury deadlock, “Well, it’s a little bit gratifying, but it’s scary because Mr. Hall is innocent.”

She said she expected the prosecution to want to retry the case, which is due back at the downtown Los Angeles courthouse May 9.

The defendant’s mother, Deborah Mosby, said she sympathized with the victim’s family, but wants police to “get the right person.” “They’re not trying to find the killer,” she told reporters shortly after the mistrial was declared, maintaining that her son had been wrongly accused.

Deputy District Attorney David Barkhurst told jurors during his closing argument that Hall went into rival gang territory and began shooting.

The prosecutor told the eight-man, four-woman panel that eyewitnesses linked Hall to the boy’s killing.

Hall’s attorney questioned the perception of the witnesses, telling jurors that “there is absolutely zero physical or forensic evidence” to show that her client was in the alley that day.

“We know eyewitnesses can be wrong,” she said. “We know that it does happen…”

Marcus Denson, who was charged along with Hall, pleaded guilty earlier to one count of voluntary manslaughter and two counts of attempted murder, according to Jane Robison of the District Attorney’s Office. Denson, 21, is awaiting sentencing in May.