Earlier in the day, Sanford Police Chief Bill Lee Jr. said he was temporarily stepping aside as a result of criticism of his investigation of the black teenager's death.
Scott and Bondi appointed State Attorney Angela B. Corey, whose office handles cases in Duval, Clay and Nassau counties. Brevard-Seminole State Attorney Norm Wolfinger, whose territory includes Sanford, relinquished the investigation after a talk today with Scott and Bondi, the governor's office said.
Martin, 17, was shot once in the chest Feb. 26 by George Zimmerman, a neighborhood watch leader in the gated community where the youth was returning home from a 7-11 store. Zimmerman, 28, scuffled with Martin and claimed he shot him in self-defense, although Martin was unarmed.
Lee said Florida law prevented him from charging Zimmerman, which has sparked outrage nationwide.
Last week, as criticism grew, Sanford police turned the investigation over to the state attorney's office. A Seminole County grand jury is to review evidence April 10.
This week, as the story exploded nationwide through social media, the Justice Department and FBI announced that they had begun a civil right investigation.
Meanwhile, thousands of people gathered in a rally in Fort Mellon Park in Sanford Thursday night, the Orlando Sentinel reported.
The Rev. Al Sharpton came from New York and took the podium nearly an hour into the rally.
Twenty-six days ago, this young man, Trayvon Martin....went to the store for his brother. He came back and lost his life, Sharpton told the cheering crowd. Trayvon represents a reckless disregard for our lives. Enough is enough. Zimmerman should have been arrested that night. You cannot defend yourself against a pack of Skittles and iced tea.
Sharpton said he was angry that Zimmerman hadn't been arrested.
Don't talk to us like we're stupid! We love our children like you love yours, Sharpton said. Lock him up!
Sharpton then introduced Trayvon's parents, Sybrina Fulton and Tracy Martin.
I stand before you today not knowing how I'm walking right now because my heart hurts for my son, Fulton said. Trayvon is my son. Trayvon is your son. Thanks so much for your support.
Martin's parents were unmoved by Lee's stepping aside, CNN reported.
The temporary step-down of Bill Lee is nothing, Trayvon's father told the rally. We want an arrest, we want a conviction, and we want a sentence for the murder of our son.
Sharpton was more strident: We did not come here for a temporary leave of absence, he said. We came for permanent justice -- arrest Zimmerman now!