(CNN) — George Zimmerman, the neighborhood watch volunteer charged with murder in the February death of Trayvon Martin, has been released on bail from a Florida jail.

Zimmerman walked out of the John E. Polk Correctional Facility in Sanford, Florida, around midnight Sunday, wearing a brown jacket and blue jeans and carrying a brown paper bag in his arms. He got into the back of a white BMW and did not speak to reporters.

It was not immediately known where he was headed.

The Seminole County Sheriff’s Office said Zimmerman was fitted with an electronic monitoring device, which can keep tabs on his whereabouts in real time.

Over the weekend, his lawyer had said Zimmerman could remain behind bars until the middle of this week due to concerns about collecting enough funds for his bond, which was set at $150,000.

With the 10% cash payment customarily made to secure bond, Zimmerman’s family needed $15,000 for him to make bail.

Attorney Mark O’Mara visited Zimmerman on Saturday, a day after county Judge Kenneth R. Lester Jr. set the bond. Prosecutors had asked that Zimmerman remain in jail without bond until trial or that it be set at $1 million.

Speaking to reporters Saturday outside the jail, O’Mara said his client is aware this is “a long, long process.”

“He’s still very worried about the fact that he’s facing a life sentence on a 2nd-degree murder charge,” O’Mara said.

Zimmerman, 28, apologized in court Friday to Trayvon Martin’s family for shooting the unarmed, black 17-year-old boy in a confrontation that has riveted the nation and sparked intense discussions about race and gun control.

“I wanted to say I am sorry for the loss of your son,” he said in an unusual appeal directly to Martin’s family before he testified in the Seminole County Courthouse in Sanford. “I thought he was a little bit younger than I was, and I did not know if he was armed or not.”

O’Mara said after the hearing that his client was responding to an interview in which Martin’s mother, Sybrina Fulton, said she wanted to hear from the man who shot her son.

“He didn’t want to defend himself, he didn’t want to discuss the facts of the case. He heard the request of the family, and he wanted to respond to it,” O’Mara said, adding that an attempt to apologize to the family in private was rebuffed.

Lawyers for Martin’s family, however, called the apology a self-serving act by a man facing a life-in-prison sentence if convicted of the second-degree murder charge.

“This was the most disingenuous, insulting thing I’ve ever seen,” said Martin family attorney Natalie Jackson.

Martin’s parents were “completely devastated” over the decision to allow Zimmerman to post bond, said another family attorney, Benjamin Crump.

Assistant State Attorney Bernie de la Rionda had argued for a higher bond total. Prior run-ins with a police officer and a woman who named him in a domestic violence injunction show that Zimmerman is violent and a threat to the community, de la Rionda said.

Lester, however, described the incidents as “run of the mill” and “somewhat mild” in approving O’Mara’s request for bond.

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The judge told O’Mara to talk to authorities about his request to allow Zimmerman to leave Florida while awaiting trial. O’Mara said he is concerned about threats to Zimmerman’s safety, as well as that of his family.

De la Rionda said no decision has been made on whether to allow Zimmerman to leave the state.

Zimmerman’s father testified Friday that when he saw his son the day after Martin’s shooting, he was wearing a protective cover over his nose, his face was swollen, and he had two vertical gashes on his head. He also reportedly suffered a broken nose.

Martin’s family and the special prosecutor appointed to investigate the case have rejected that argument, saying they believe Zimmerman disobeyed the instructions of a police dispatcher to stop following Martin, racially profiled him and unjustly killed him.

Timeline of case

Although details of the shooting remain murky, what is known is that Martin ventured out on February 26 from the home of his father’s fiancee in Sanford and went to a nearby convenience store, where he bought a bag of Skittles and an Arizona Iced Tea.

On his way back, he had a confrontation with Zimmerman, who shot him.

Zimmerman had called 911 to complain about a suspicious person in the neighborhood, according to authorities.

In the call, Zimmerman said he was following Martin after the teen started to run, prompting the dispatcher to tell him, “We don’t need you to do that.” Zimmerman pursued Martin anyway.

Florida to review ‘stand your ground’ law

After briefly losing track of the teen, Zimmerman told authorities the teen approached him and the two exchanged words. Zimmerman said he reached for his cell phone, then Martin punched him in the nose. Zimmerman said Martin pinned him down and began slamming his head onto the sidewalk, leading to the shooting.

Police have said Zimmerman was not immediately charged because there was no evidence to disprove his account that he had acted in self-defense. A police report indicated he was bleeding from the nose and the back of his head.

O’Mara said Saturday that he expects the prosecution was holding back some evidence that is key to its case during Friday’s court hearing.

“I’m sure the state has a lot more information,” the lawyer said, describing what was presented Friday as “snippets of the evidence.” “I’m just looking forward to getting it.”

CNN’s Vivian Kuo, Leslie Tripp Holland and Holly Yan contributed to this report.