'Loud-music' jury stuck on one count

• "They're struggling, obviously," judge says of the jurors


• Michael Dunn opened fire on 4 teens in an SUV in 2012, killing 17-year-old Jordan Davis


• He's charged with first-degree murder; if convicted, he faces up to life in prison


• Dunn says he was acting in self-defense

(CNN) -- Within half an hour of resuming deliberations Saturday in the case against Michael Dunn, accused of shooting and killing an unarmed teenager in Florida after he had asked him to turn down the music in the SUV he and three other youths were in, jurors submitted a list of three questions to the judge.

"They're struggling, obviously, but it's not for want of trying to reconcile all of this," Judge Russell L. Healey told the courtroom early Saturday, after the jurors had spent some 20 hours in deliberation and before he called them back to the courtroom to answer the questions. "I think we've got some analytical people in there who are trying to do just that -- trying to analyze this from every possible angle."

The questions and answers:

-- "Is the defense of self-defense separate for each person in each count?" Judge: "Yes."

-- "Are we determining if deadly force is justified against each person in each count?" Judge: "Yes."

-- "Or, if we determine deadly force is justified against one person, is it justified against the others?" Judge: "No. Self-defense and justifiable use of deadly force applies separately to each count."

With that, he sent them back to the jury room for further deliberations.

Dunn is charged with first-degree murder in the November 2012 death of 17-year-old Jordan Davis in Jacksonville. He was one of four black teenagers who were in an SUV fired upon by Dunn -- who is white.

The violence erupted after an argument over loud music.

Some have compared the Dunn case to the trial of George Zimmerman in the killing of Florida teenager Trayvon Martin, which, like the current trial, had racial overtones and claims of self-defense.

In a statement, Trayvon Martin's parents Tracy Martin and Sybrina Fulton said Davis' killing was another reminder that in Florida, "racial profiling and stereotypes" may serve as the basis for illegitimate fear "and the shooting and killing of young teenagers."

Whatever the verdict, Davis' parents, Ron Davis and Lucia McBath, will never see their son again, they noted, adding, "We know that pain all too well. We walk with Jordan in defining his legacy to reflect our hopes by advancing love and tolerance in his memory, and continuing the fight against unjust gun laws."

"Tomorrow is my boy's 19th birthday," his mother tweeted Saturday. "I pray we will celebrate not only him but a just and righteous verdict. Patiently we wait."

But Dunn's defense attorney Cory Strolla told CNN's Chris Cuomo on Friday that the Zimmerman and Dunn cases aren't so similar.

There was a physical confrontation between Zimmerman and Martin, and police gave Zimmerman the benefit of the doubt about defending himself, Strolla said.

"My client did not wait to become that victim; my client did not wait to either get assaulted by a weapon or have someone potentially pull a trigger," he said.

Unlike the Zimmerman case, police rushed to charge Dunn with murder, the defense attorney said.

"They already made up their mind before they even had the evidence basically looked at and put together," he said.

Though a weapon was never found, Strolla maintains the youths could have had one. Dunn felt threatened and acted to defend himself, he said.

"Now, does it sound irrational? Of course it sounds irrational. But have you ever been in that situation," Strolla asked.

Jury cannot decide

The jury in Dunn's case deliberated all day Friday, then sent a message to the judge shortly before 7 p.m. that they had "reached a wall for the evening."

"This is one admirable group," Healey told the court shortly before dismissing the jury. "They are clearly taking this thing as seriously as they should. And I couldn't be more proud of them for how hard they are working."

The announcement capped a relatively uneventful day Friday after what had been an emotional trial.

Prosecutors contend that Dunn's firing into the SUV was an act of murder in the first degree. He is also charged with three counts of attempted murder and a fifth count of shooting or throwing deadly missiles. If found guilty, he faces up to life in prison.

In the wake of the widespread attention that the case has attracted, a "comprehensive public safety plan" has been established ahead of a verdict, according to the Duval County joint information center handling the Dunn trial.

"All contingencies have been planned for," the statement said. "We will not discuss the specifics of any security plan. We will continue to protect the rights of those who choose to peaceably demonstrate."

CNN's Sunny Hostin, AnneClaire Stapleton and John Couwels contributed to this report.