FORT PIERCE, Fla. — The St. Lucie County Sheriff's Office said Thursday that the man who was once a person of interest in a deadly mass shooting at Ilous Ellis Park in Fort Pierce earlier this week is no longer a person of interest.
Frederick Johnson Jr., 27, turned himself in to authorities Wednesday after he was wanted for violation of probation.
Chief Deputy Brian Hester said Wednesday that Johnson was a person of interest in a Martin Luther King Jr. Day. shooting in which eight people were shot during a holiday celebration at the park, located near Avenue M and 13th Street.
However, the sheriff's office Thursday morning posted an update on Facebook, saying that, "After speaking with Johnson, detectives have determined that Johnson is no longer a person of interest at this time."
Johnson appeared before a St. Lucie County judge Thursday morning. He was denied bond for violation of probation, which authorities said stemmed from drug-related charges.
During a Thursday afternoon news conference, St. Lucie County Sheriff Ken Mascara said his agency had every available person working on the shooting case around the clock.
"We're not going to stop until there's an arrest," Mascara said. "We are working hard on this case."
Mascara said unfortunately there were no surveillance cameras in the park that might help in their investigation.
The sheriff made a passionate plea for members of the public to come forward to share tips to help detectives.
WATCH: Sheriff Ken Mascara holds Thursday afternoon news conference
"We need people to share with law enforcement what they know, what they saw so that we can stop the violence," Mascara said.
He said they've had anonymous people call in with information, but detectives are hampered when the tipster won't offer contact info for follow-up questions.
Mascara was ardent that the community was safe, and that this wasn't a random mass shooting.
"Someone just didn't walk into the park with an automatic weapon and start firing," Mascara said. "The shooting occurred between two known individuals who got into an argument and decided to resolve their differences with gunfire."
The sheriff wouldn't say if his agency had any suspects in the case but said "we will make an arrest" at some point.
One of the victims of Monday's shooting, Nikkitia Bryant, 29, died from her injures at HCA Florida Lawnwood Hospital.
The St. Lucie County Sheriff's Office has set up a dedicated hotline specifically to gather leads in the case. Call 772-462-3230 or Treasure Coast Crime Stoppers at 800-273-8477.