SANFORD -- The aftershocks of Trayvon Martin’s killing continued to reverberate Thursday from Sanford to South Florida, as the embattled police chief and state attorney overseeing the investigation stepped down hours after more than 1,000 Miami-Dade high school students staged a walkout to protest the lack of criminal charges in the case.

Angela Corey, the state attorney for Duval, Nassau and Clay counties, will serve as special prosecutor in the case, Gov. Rick Scott’s office announced Thursday night. The government’s statement suggested that Brevard-Seminole State Attorney Norm Wolfinger was forced out.

Scott also created a statewide citizen task force to review Florida’s controversial “Stand Your Ground” law.

The governor’s news was welcomed with boisterous cheers by thousands of people gathered in a Sanford park to attend a rally with the Rev. Al Sharpton, who led the event despite the death of his mother. Flanked by Trayvon’s parents, Tracy Martin and Sybrina Fulton, the celebrity civil-rights activist said Sanford Police Chief Bill Lee’s decision to temporarily step down was not enough.

“We didn’t come here for a temporary leave of absence,” Sharpton said. “We came here for permanent justice. Arrest Zimmerman now!”

George Zimmerman, 28, was the neighborhood watch captain at the Retreat at Twin Lakes, a townhouse complex in the small town north of Orlando. A Hispanic former insurance agent with a history of reporting the presence of black men to police, Zimmerman shot Trayvon in the chest on Feb. 26. The killing came after Zimmerman called police saying he saw someone in a hoodie walking too slowly in the rain, peering at houses. After the shooting, he told police he was attacked and fired in self defense.

A general studies major at Seminole State College, Zimmerman was kicked out of the school Thursday “due to the highly charged and high-profile controversy,” the school announced.

The Sanford Police Department is under fire for its handling of the investigation and for accepting the shooter’s self-defense claim. Accused of lying to reporters and Trayvon’s parents, protecting the shooter and ignoring key witnesses, Lee decided to step aside Thursday. His decision came a day after a 3-2 Sanford city commission vote of “no confidence” in the chief.

“As a former homicide investigator, career law enforcement officer and a father, I am keenly aware of the emotions associated with the tragic death of a child,” Lee said at a brief press conference. “While I stand by the Sanford Police Department, its personnel and the investigation that was conducted in regards to the Trayvon Martin case, it is apparent that my involvement in this matter is overshadowing the process…. I do this in the hopes of restoring some semblance of calm to the city, which has been in turmoil for several weeks.”

Two captains will run the department until an interim chief is chosen, City Manager Norton Bonaparte Jr. said. It was unclear whether Lee planned to return to the $102,000-a-year post.

On the job for just 10 months, Lee joined the department after a 27-year career at the Seminole County Sheriff’s Office with a mission to clean up a department marked by internal turmoil and race-related scandals.

Trayvon’s mother, who works at the Miami-Dade housing authority, called the chief’s move a “temporary relief.”