SANFORD, Florida (AP) — The Florida police chief who has been bitterly criticized for not arresting a neighborhood watch volunteer in the shooting death of an unarmed black teenager temporarily stepped down Thursday, saying he had become a distraction to the investigation.

Sanford Police Chief Bill Lee and his officers decided not to arrest George Zimmerman after he shot 17-year-old Trayvon Martin to death on Feb. 26. 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 claims the shooting was self-defense. He told police 17-year-old Trayvon 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. Late Wednesday, city commissioners gave the police chief a “no confidence” vote.

WATCH BILL LEE’S STATEMENT TO THE PRESS HERE:

Visit msnbc.com for breaking news, world news, and news about the economy

“I must temporarily remove myself from the position as police chief for the city of Sanford. 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. “It is my hope that the investigation will move forward swiftly and appropriately through the justice system and that a final determination in this case is reached.”

The police chief has said authorities were prohibited from making an arrest based on the facts and circumstances they had at the time of the shooting. He said he continued 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.

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.

Some people believed the Lee should step down for good.

“If they wanted to diffuse 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 1,000 protesters who had shown up more than two hours before the start of the rally Thursday. 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 said: “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.

Copyright 2012 The Associated Press.