The split came as special prosecutor Angela Corey neared a decision on whether to charge Zimmerman with a crime in the Feb. 26 shooting.
That decision could come later this week, as Corey released a brief statement late Tuesday saying she would make an announcement about the case within 72 hours. She did not specify what new development in the case would be released.
Sonner and colleague Hal Uhrig said they had not spoken with Zimmerman since Sunday. Since then, they said, they had learned that he spoke to Corey's office and to Fox TV host Sean Hannity without consulting them, in an attempt to give his side of the shooting. They said Corey refused to talk to Zimmerman without his attorneys' consent and Hannity wouldn't tell them what was discussed.
Zimmerman also set up his own website even as the lawyers were creating one for him at his request. Zimmerman said on his website that he wants "to ensure my supporters they are receiving my full attention without any intermediaries." The site allows visitors to give Zimmerman money for living expenses and legal bills.
Sonner and Uhrig said that they still believe in Zimmerman's innocence and that they would probably represent him again if he contacted them and requested it. They said Zimmerman is in the U.S., but wouldn't say where because they fear for his safety.
They said Zimmerman has been under extreme pressure and is basically alone, having gone underground because of the furor.
"This has been a terribly corrosive process. George Zimmerman, in our opinion, and from information made available to us, is not doing well emotionally, probably suffering from post-traumatic stress syndrome. We understand from others that he may have lost a lot of weight," Uhrig said.
"To handle it this way suggests that he may not be in complete control of what's going on. We're concerned for his emotional and physical safety."
Ben Crump, an attorney for Martin's family, said they are worried that Zimmerman might flee if he is charged.
"We're just concerned that nobody knows where he is at. Nobody knows how to get to him," Crump said.
Kendall Coffey, a former U.S. attorney in Miami who is now in private practice, questioned the way the lawyers publicly cast doubt on Zimmerman's mental stability.
"The lawyers have every right to withdraw, but it's highly unusual, and it will be controversial, for counsel to describe their client's erratic behavior," Coffey said. "In the court of public opinion, the press conference was not helpful for George Zimmerman."
In a case that has stirred a furious national debate over racial profiling and self-defense, Zimmerman, 28, shot Martin, 17, after he spotted the teen walking through the gated community in Sanford. Zimmerman's father is white and his mother is Hispanic.
Zimmerman said Martin attacked him, and he claimed self-defense under Florida's "stand your ground" law, which gives people wide leeway to use deadly force. Martin's family has said the evidence suggests Zimmerman was the aggressor.
Meanwhile, tensions were rising in Sanford as townspeople awaited the prosecutor's decision. Someone shot up an unoccupied police car Monday night as it sat outside the neighborhood where Martin was killed. And a demonstration by college students closed the town's police station earlier in the day.
Some residents said they worry there will be violence if Corey decides not to charge Zimmerman. The prosecutor has not said when she will announce her decision, but many in town believe it will be soon.
Police aren't saying what, if any, precautions they are taking.
Eddie Jones, a 58-year-old black man and lifelong resident of Sanford, said Zimmerman's arrest is paramount to keeping the protests peaceful.
"They need to go ahead and arrest this guy before something happens," he said. "Sanford is screwed up. This place just didn't get corrupt."
While tensions are high, some think this city of about 53,000 - around 57 percent white and 30 percent black - will come through the crisis without violence, as it did during similar uproars.
Two years ago, after a black homeless man was beaten by the son of a Sanford policeman, passions soon cooled. The assailant, Justin Collison, initially wasn't charged but eventually was arrested after footage of the episode went viral on YouTube. He pleaded guilty to a misdemeanor and received probation.
James Carder, a mechanic at McRobert's Auto Center, put a message on his shop that was readily visible to anyone driving down First Street: "Sanford is still a good little town."
Until the Martin shooting, Sanford was probably best known as the Florida stop for the Auto Train, the Amtrak line that carries tourists and their cars between suburban Washington and central Florida's theme parks.
"I put it up because I do care about my good little town," said Carder, who is white. "It has problems just like everywhere. But it's still a good little town. It always has been and always will be."
