City officials in Florida have blocked the resignation of the police chief who did not arrest the man who shot and killed unarmed teenager Trayvon Martin.
Sanford police chief Bill Lee tendered his resignation on Monday, the day shooter George Zimmerman - now facing a murder charge - was released on bail.
City officials later voted 3-2 to block Mr Lee's resignation.
George Zimmerman, 28, is facing a charge of second-degree murder for shooting Trayvon Martin, 17.
In a court document released on Monday it emerged that Mr Zimmerman has pleaded not guilty to the charge, which carried a possible life sentence.
The court may now waive the requirement for him to appear at an arraignment hearing on 8 May, the document suggests.
He says he acted in self-defence on the night Trayvon Martin died, opening fire after coming under physical attack.
Under Florida's so-called "stand your ground" law it is not a crime to use lethal force if a person feels they are seriously under threat.
Mr Zimmerman was patrolling the streets of his gated community in Sanford, on the outskirts of Orlando, when he encountered Trayvon Martin on the night of 26 February.
In Sanford on Monday, the five city commissioners convened a special meeting to discuss the police chief's offer to resign.
One of Mr Lee's backers, commissioner Patty Mahany, called him "one of the finest police officers in Florida," the Orlando Sentinel reported.
"This is not right. Just on a human level," she said, adding that attacks against the police chief were "solely political", despite the same board having censured him with a vote of no-confidence a month ago.
There was a feeling that there could be "no healing" if he stayed on in his office, she said.
Antipathy against the police has run high in Sanford since the killing of Trayvon Martin, especially among the city's black community.
Earlier, George Zimmerman was released from prison on bail as he awaits trial for the killing. He left Seminole County jail late on Sunday night on a $150,000 (£93,000) bond.
His ultimate destination, which could be outside Florida, was being kept secret for his safety.
Mr Zimmerman, who says he shot the teenager in self-defence, made no comment to journalists as he left the prison.
Wearing a brown jacket, jeans and carrying a paper bag, he was met by another man and got into a white BMW before driving away.
At Mr Zimmerman's bail hearing last week, the judge said he must inform police of his location every three days and stick to a dusk-to-dawn curfew.
He will also be tracked electronically and is forbidden from carrying firearms, drinking alcohol, or contacting the victim's family personally or through an intermediary.
In court on Friday, Mr Zimmerman apologised to Trayvon's parents, saying he did not realise the schoolboy's age, or that he was unarmed. However, a lawyer for the family rejected the apology.
The accused's attorney, Mark O'Mara, told CBS's This Morning programme on Monday that his client would not have apologised during Friday's hearing if he had known the family felt it was the wrong time.
A lawyer representing the dead teenager's parents, Daryl Parks, said on Monday that the family was "devastated by him [Mr Zimmerman] being able to walk the streets".
"It's with a very, very heavy heart that they've seen him walk freely late last night back into the public," Mr Parks told CNN.
The death of Trayvon Martin has divided the US, and sparked nationwide protests calling for Mr Zimmerman's arrest.
According to an affidavit of probable cause, Trayvon Martin was walking home from a local shop carrying a bag of sweets and a can of iced tea when he was "profiled" by Mr Zimmerman.
The document notes that Martin, who was visiting his father's fiancee's home, was unarmed but Mr Zimmerman assumed he was a criminal.
The neighbourhood watch volunteer had told a police dispatcher he thought Martin, who was wearing a hooded sweatshirt, looked suspicious.
Mr Zimmerman was advised by the police dispatcher not to go after the young man. But minutes later a confrontation ensued in the gated community, leading to the fatal shooting.