SANFORD, Florida (CNN) -- Special prosecutor Angela Corey has decided against using a grand jury in the case involving the shooting death of 17-year-old Trayvon Martin, her office said Monday.
"The decision should not be considered a factor in the final determination of the case," the office said in a statement.
The grand jury, set to convene Tuesday, was "previously scheduled by the former prosecutor," the statement said.
Corey said the investigation into the case continues. The state attorney has maintained that a grand jury is not needed to file possible criminal charges against George Zimmerman, the neighborhood watch volunteer who killed the teen February 26.
"We were anticipating that there would be no grand jury, because the family has always been hopeful that there would just simply be an arrest," said Benjamin Crump, an attorney for the Martin family. "We believed, from day one, that they had enough evidence to arrest the killer of Trayvon Martin and now, as the evidence has continued to unfold, we think there has been a plethora of evidence to simply effect probable cause to do an arrest -- not for a conviction, but for an arrest."
Crump said the family is hoping for charges against Zimmerman and an arrest as soon as possible.
"We want a very public trial so the evidence can come out and show people that the justice system works for everybody," he said.
He told CNN that the victim's mother, Sybrina Fulton, "said that she's prayerful" Zimmerman will be arrested.
The Justice Department said the grand jury decision does not affect any federal role. "The department's parallel investigation remains ongoing," Justice spokeswoman Xochitl Hinojosa said.
"We hope this decision signals the special prosecutor's intention to live up to her reputation as a passionate, justice-focused attorney and bring charges against Zimmerman herself," said NAACP President and CEO Benjamin Todd Jealous. "The future of this case now rests solely with her and we have faith that she will do her best to secure justice for Trayvon Martin."
The case has triggered a nationwide debate about race in America and Florida's "stand your ground" law, which allows people to use deadly force anywhere they feel a reasonable threat of death or serious injury.
Prosecutors are trying to unravel what happened the night Martin was killed. Witnesses and attorneys for both sides have offered conflicting accounts. Two prosecutors are working to determine whether there is sufficient evidence to bring charges against Zimmerman.
Zimmerman's attorney, Hal Uhrig, texted his reaction to CNN's Martin Savidge about Corey's decision to not use a grand jury: "Not surprised. Don't know what her decision will be. Courageous move on her part."
Uhrig said he and Zimmerman legal adviser Craig Sonner plan to meet with Zimmerman for the first time "probably later this week."
Corey said previously that she had never used a grand jury to decide on charges in a justifiable homicide case.
"We do a thorough investigation. We make that decision ourselves," she said.
Sunny Hostin, legal analyst for CNN sister network HLN, said she was not surprised by Corey's decision.
"As a former prosecutor, I typically made my own charging decisions," she said. "... Many, many seasoned prosecutors use their judgment and make charging decisions, don't necessarily punt the ball to lay people, to a grand jury."
Corey's decision was "the smart thing to do," she said. "... Now Angela Corey is letting everyone know that this is her case. This is her decision."
Thousands have converged on Sanford to join in protests calling for Zimmerman's arrest and criticizing the police department's handling of the case.
On Monday, a group of students calling themselves the Dream Defenders marched to the Sanford police station, singing and carrying a banner saying, "We are Trayvon Martin." The march began Friday in Daytona Beach, about 40 miles away, and continued through the weekend.
The marchers linked arms, sang and chanted as they faced the building's entrance Monday. Six of the demonstrators, wearing hoodies, were blocking the department's main entrance. Martin was wearing a hoodie when he was killed.
The Sanford Police Department reopened Monday after closing temporarily when student protesters blocked the department's main entrance. Prior to their departure, City Manager Norton Bonaparte Jr. and Acting Police Chief Darren Scott met with leaders of the student group and community leaders.
Although details of the February 26 incident remain murky, what is known is that Martin ventured out from his father's fiancee's home in Sanford to get a snack at a nearby convenience store. As he walked home with a bag of Skittles and an Arizona iced tea, he was shot and killed by Zimmerman.
Sanford police questioned Zimmerman and released him without charges. From there, the case has evolved into opposing allegations from Zimmerman's supporters, Martin's family and authorities.
Zimmerman says he killed Martin in self-defense after the teen punched him and slammed his head on the sidewalk, according to an Orlando Sentinel report that was confirmed by Sanford police.
A police report said one of the responding officers saw a wound on the back of Zimmerman's head and a bloody nose, and noted that his back was wet -- indicating he had been lying in grass. "I was yelling for someone to help me, but no one would help me," he told authorities, according to the police report.
An enhanced copy of a surveillance video showing him in police custody after the shooting appears to show a bump, mark or injury on his head. Martin's family and supporters have dismissed the video.
They say Zimmerman, who is Hispanic, racially profiled the teen, who was black, and ignored a police dispatcher's directive not to follow him.
Zimmerman's attorneys interpret the call differently and say the operator did not order Zimmerman not to follow Martin.
On the 911 call, the dispatcher asked Zimmerman if he is following Martin. Zimmerman says "yeah," and the dispatcher replies, "OK. We don't need you to do that."
A recording of another 911 call, made minutes later, apparently by someone in the neighborhood, captured a voice yelling for help. Martin's relatives have said they are certain the voice calling for help is Martin's.
Audio experts Tom Owen and Ed Primeau, who analyzed the recordings for The Orlando Sentinel using different techniques, said they don't believe the voice is Zimmerman's. They compared the screams with Zimmerman's voice, as recorded in his 911 call.
However, others have cautioned against drawing conclusions about those findings, given the fact the tests did not analyze similar speech.
The debate was further muddied when a witness, who declined to be identified publicly, told CNN she saw and heard the incident through her window.
When pressed on whether she could determine who was yelling, the witness said, "It was the younger, youthful voice (rather) than it was the deep voice I heard when they were arguing."
Zimmerman's attorneys have questioned the account, saying it was dark at the time of the shooting. Until now, friends and relatives of Zimmerman -- but not Zimmerman himself -- have come forward to speak on his behalf. Zimmerman's attorneys have said he wants to share his story but can't because of threats to his safety and the possibility of charges.
Martin's family has said a Sanford police detective filed an affidavit saying he did not find Zimmerman's statements after the shooting credible -- but that Sanford Police Chief Bill Lee and State Attorney Norm Wolfinger met the night of the shooting and disregarded the detective's advice.
Neither police nor prosecutors have confirmed the existence of such an affidavit. And Wolfinger has denied that such a meeting occurred.
The two sides have also debated what Zimmerman may have whispered under his breath during his 911 call.
Martin's supporters said he uttered a racial slur; Zimmerman's lawyer said he told them he whispered "punks" -- an assertion that experts backed up.
Gov. Rick Scott appointed Corey as a special prosecutor as calls for "Justice for Trayvon" grew in the days following the shooting.
Authorities have said Zimmerman was not immediately charged because there were no grounds, at the outset, to disprove his account that he'd acted to protect himself. The governor has formed a task force to review the "stand your ground" law.