Updated 3:35 p.m. ET
(AP) SANFORD, Fla. - Neighborhood watch volunteer George Zimmerman made his first court appearance Thursday on a second-degree murder charge in the shooting death of Trayvon Martin, as a court document provided new details on the prosecution's case.
During the brief appearance, Zimmerman stood up straight, looked straight ahead and wore a gray prison jumpsuit. He spoke only to answer "Yes, sir," twice after he was asked basic questions about the charge against him and his attorney.
His hair was shaved down to stubble and he had a thin goatee, which appeared consistent with his booking photo from the day before. He had resurfaced Wednesday to turn himself in after weeks in hiding.
Judge Mark E. Herr said he found probable cause to move ahead with the case and that an arraignment would be held on May 29 before another judge. At a press conference following the court appearance, Zimmerman's attorney Mark O'Mara said he will seek a bond hearing "in the next few weeks." Zimmerman is expected to enter a not guilty plea. O'Mara said he was working on finding a place Zimmerman could safely stay if he is released before trial.
The affidavit of probable cause prepared by prosecutors shed some light on why they chose to charge Zimmerman. The Orlando Sentinel said it had obtained a copy before it was expected to be filed with the courthouse.
The newspaper says that Martin's mother identified screams heard in the background of a 911 call as her son's. There had been some question as to whether Martin or Zimmerman was the one calling for help.
Prosecutors also interviewed a friend of Martin's who was talking to him just before the shooting. The affidavit says Martin told the witness he was being followed and was scared.
Martin tried to run home, the affidavit says, but was followed by Zimmerman: "Zimmerman got out of his vehicle and followed Martin."
The affidavit says that "Zimmerman disregarded the police dispatcher" who told him to stop, and "continued to follow Martin who was trying to return to his home."
Speaking to reporters after the hearing, O'Mara said he was concerned that the case up to now has been handled in the public eye, with details coming out in piecemeal fashion.
"It's really supposed to happen in the courtroom," O'Mara said, deflecting questions about evidence in the case and his client's mental state.
"He's tired," O'Mara said when asked about Zimmerman's condition. "He's gone through some tribulations of his own, being the focus of the intensity of this event. ... He's facing second degree murder charges now. He's frightened. That would frighten any one of us."
Prosecutors face steep hurdles to win a second-degree murder conviction against Zimmerman, experts say.
Zimmerman was charged after a public campaign to make an arrest in the shooting that galvanized the nation for weeks. Now the prosecutor and her team will have to prove Zimmerman intentionally went after Martin instead of shooting him in self-defense, to refute arguments that a Florida law empowered him to use deadly force.
Zimmerman, 28, turned himself in at a county jail Wednesday after prosecutor Angela Corey announced the charge in the Feb. 26 shooting of the 17-year-old that set off a nationwide debate about racial profiling and the rights to self-defense.
CBS This Morning" Thursday that he plans to because Zimmerman posed no flight risk. (Watch interview at left.)
"We just need to sort of take it one day at a time," O'Mara told co-hosts Erica Hill, Gayle King and Charlie Rose.
On Wednesday, O'Mara said Zimmerman was concerned about getting a fair trial.
"He is a client who has a lot of hatred focused on him. I'm hoping the hatred settles down ... he has the right to his own safety and the case being tried before a judge and jury," O'Mara said.
Trayvon Martin's parents, Sybrina Fulton and Tracy Martin, said on "CBS This Morning" that they were "at ease," "excited" and "overwhelmed" by Zimmerman's arrest.
However, Fulton, who has campaigned with the rest of the family for an arrest and prosecution, said she thought the shooting was an accident.
Asked on NBC's "Today" what she would say to Zimmerman face-to-face, Fulton said she wanted an apology, then added: "I believe it was an accident. I believe that it just got out of control and he couldn't turn the clock back." She did not say more about how she thinks the shooting happened.
Legal experts said Corey chose a tough route with the murder charge, which could send Zimmerman to prison for life if he's convicted, over manslaughter, which usually carries 15-year prison terms and covers reckless or negligent killings.
The prosecutors must prove Zimmerman's shooting of Martin was rooted in hatred or ill will and counter his claims that he shot Martin to protect himself while patrolling his gated community in the Orlando suburb of Sanford. Zimmerman's lawyers would only have to prove by a preponderance of evidence a relatively low legal standard that he acted in self-defense at a pretrial hearing to prevent the case from going to trial.
There's a "high likelihood it could be dismissed by the judge even before the jury gets to hear the case," Florida defense attorney Richard Hornsby said.
Corey announced the charges Wednesday after an extraordinary 45-day campaign for Zimmerman's arrest, led by Martin's parents and civil rights activists, including the Rev. Al Sharpton and the Rev. Jesse Jackson. Protesters wore hooded sweatshirts like the one Martin had on the night of the shooting. The debate reached all the way to the White House, where President Barack Obama observed last month: "If I had a son, he'd look like Trayvon."
Corey would not discuss how she reconciled conflicting accounts of the shooting by Zimmerman, witnesses and phone recordings that indicated Martin thought Zimmerman was following him.
"We do not prosecute by public pressure or by petition. We prosecute based on the facts on any given case as well as the laws of the state of Florida," Corey said.