Travis Beckford, 17, of Brooklyn, was arrested Tuesday morning, Robert Boyce, chief of detectives for the New York Police Department, told reporters.
"He is the fifth person that we have arrested in this case, and we believe he's the final person," Boyce said.
Beckford, like four other teens arrested earlier, has been charged as an adult with rape, committing a criminal sex act and sex abuse, the NYPD said.
The other teens, police said, are Denzel Murray, 14; Shaquell Cooper, 15; Ethan Phillip, 15; and Onandi Brown, 17. All have Brooklyn addresses.
As of Thursday evening, three teens have made bail. The other two will be released, authorities said.
"Because we are determined to get to the truth about what happened in that park, we need more time to investigate this complex case and gather more evidence," Brooklyn District Attorney Ken Thompson said. "So, therefore, we have consented to the defendants' release."
The district attorney can seek an indictment against any of the five suspects within the next six months, but their release falls under the New York Criminal Procedure Law, which stipulates that without a charge or dismissal, detainees must be released after six days.
Father told to leave
Police say the alleged rape took place last week at Osborn Playground.
The 18-year-old woman was with her father when they were approached by five males, police said.
One of the teens pulled a gun on them and demanded the father leave, police said.
Each of the five assailants then raped the teenager, authorities said.
The father told CNN affiliate WABC
he was near the handball court with his daughter having a drink when the men came.
"One of them put a gun in my face, telling me to run, and all of them had their way with her," the father told WABC.
He said he didn't have a cell phone with him and went to a store, begging for help -- but said people in the store wouldn't call police.
Law enforcement sources told CNN that the father ran into a nearby bodega screaming, but a man working at the bodega didn't understand what he was talking about and asked him to leave the store.
The bodega worker said the father appeared drunk or incoherent, according to the sources.
Those sources say the father and daughter were drinking beer in an obscured spot on the playground in an effort to hide from police.
By the time the father returned to the park with two police officers, the attackers were gone, police said.
'I didn't know what to do'
The young woman told WABC she screamed for help, but no one stopped.
"I didn't know what to do," she said. "I was in a panic mode."
She suffered cuts to her arms, neck and knees during the assault, police spokeswoman Arlene Muniz said. The teen was taken to a hospital, where she was treated and released.
The young woman, law enforcement sources said, was drunk and combative, and investigators could not interview her the night of the attack. She bit one police officer and refused to be transported to the hospital, the sources told CNN.
"It's a really tragic story. I've lived here my whole life. My family lived here their whole life and I never heard of anything like this," said Natalie Garcia, a young mother who lives around the corner from the playground with her 3-year-old daughter.
"My daughter plays in this park. I've played in this park when I was younger, and it's just really scary and it's to the point that what are we gonna do about it?"
Of the suspects in custody, at least two of the teens turned themselves in and at least two others were apprehended, police said.
The 14-year-old suspect and one of the 15-year-old suspects were turned in by their mothers after the mothers saw surveillance video, according to Sgt. Daniel Doody.
Authorities released video that they say shows the five attackers at a local store before the incident.
Kenneth Montgomery, an attorney representing the 14-year-old suspect, told CNN he has seen a separate cell phone video.
"What it shows, I think, contradicts the synopsis given by the government as to what happened," Montgomery said. "It's compelling."
Montgomery would not share the purported video with CNN.
An NYPD spokesman said that police are seeking access to a cell phone that may contain video taken before the incident by one of the suspects.
A Kings County District Attorney spokesperson tells CNN: "All aspects of this case are being investigated, and we will evaluate every piece of evidence."
At least one of the suspects in custody told investigators the sex was consensual, law enforcement sources have said.
A gun has not yet been recovered, and the results of the young woman's rape kit are pending, said Doody.
"I am disgusted and deeply saddened by the horrific attack that took place in Brownsville Thursday evening," Mayor Bill de Blasio said.
"Every New Yorker in every neighborhood deserves to feel safe and protected, and we will not stop until the perpetrators of this disturbing attack are held accountable for their actions. This administration has zero tolerance for sexual attacks, and we will work to ensure a crime of this nature never happens again."