SANFORD, Fla. >> The police chief who has been bitterly criticized for not arresting a neighborhood watch volunteer in the shooting death of an unarmed black teenager announced Thursday that he is temporarily stepping down to let passions cool.

Sanford Police Chief Bill Lee’s decision came less than a day after city commissioners gave him a "no confidence" vote, and after a couple of weeks of protests and uproar on social media websites. Lee has said evidence in the case supported George Zimmerman’s claim that the Feb. 26 shooting of 17-year-old Trayvon Martin was self-defense.

"I do this in the hopes of restoring some semblance of calm to a city which has been in turmoil for several weeks," Lee said.

Martin was returning from a trip to a convenience store when Zimmerman started following him, telling police dispatchers he looked suspicious. At some point, the two got into a fight and Zimmerman pulled out his gun.

Zimmerman told police Martin attacked him after he had given up on chasing the teenager and was returning to his sport utility vehicle.

The shooting ignited racial tensions in this Orlando suburb. Civil rights groups have held rallies in Florida and New York, saying the shooting was unjustified.

The police chief continued Thursday to stand behind his agency’s investigation.

"As a former homicide investigator, a career law enforcement officer and a father, I am keenly aware of the emotions associated with this tragic death of a child. I’m also aware that my role as a leader of this agency has become a distraction from the investigation," Lee said.

It wasn’t immediately how long the police chief would step aside. Martin’s parents said that wasn’t enough, and that Zimmerman should be taken into custody.

"We want an arrest, we want a conviction and we want him sentenced for the murder of my son," Martin’s father, Tracy, said to fiery crowd of about 1,000 supporters in downtown Sanford.

Some people believed the police chief should step down for good.

"If they wanted to defuse a potential powder keg, he needed to resign," said pastor Eugene Walton, 58, who was born and raised in Sanford. "His inaction speaks loudly to the black community."

News of the police chief’s decision to step aside spread quickly among the protesters, many of whom showed up more than two hours before the start of the rally. They chanted "The chief is gone. Zimmerman is next."

Some carried signs that said: "100 years of lynching, justifiable homicide. Same thing." Others sold T-shirts that read: "Arrest Zimmerman."

"It’s the norm around here, where anything involving black culture, they want to wipe their hands of it," said Shella Moore, who is black and grew up in Sanford.

The Justice Department and FBI have opened a civil rights investigation, and the local prosecutor has convened a grand jury April 10 to determine whether to charge Zimmerman.

Before the rally, Martin’s parents met with the local U.S. attorney, the deputy assistant attorney general for civil rights in Washington and the head of the FBI’s Tampa office to discuss the investigation.

"We listened carefully to the concerns of the family and their representatives," Special Agent Dave Couvertier, an FBI spokesman, said in a statement. "We continue to extend our deepest condolences to Trayvon’s family for their loss."