Charges for Andre Jackson were dropped, and he is being released after being charged with Josue's murder over a year ago.
Josue was 11 years old when he was stabbed to death while walking home from Marshall Middle School last May.
WATCH: Timeline of the Josue Flores case
In early June of 2016, 27-year-old Jackson was arrested. But the Harris County District Attorney's Office said his release comes down to DNA.
The DA said the results of the DNA in a blood analysis are "at best inconclusive" and "in some ways exclude" Jackson as a suspect.
No other suspects have been named, however, and prosecutors said Jackson remains a suspect despite their lack of enough evidence to convict him.
Jackson's attorney said these developments don't surprise him because he was convinced he could not have committed Josue's murder.
As the prosecution begins its case once again, there is a new call for the public to come forward with information to catch Flores' killer.
Josue's family said they are "devastated" after learning the charges were dropped against Jackson, who they still believe killed the boy.
In a statement to Eyewitness News, his sister Guadalupe Flores asked for privacy as she and her family deal with this new information.
"We are too devastated and broken up that a killer is being let loose due to insufficient evidence," Guadalupe Flores said.
"I know it doesn't matter what I think, but in my heart I know that he is the killer. But I know there's not enough evidence for them to keep him in jail, but that's how the system goes. If they don't have any evidence they have to let you go," she said.
Josue would have turned 12 last August.
But on May 17, 2016, Josue was stabbed 20 times. Jackson admitted he was in a video taken near the scene.
A veteran who knows Jackson said he was in total shock over the arrest. He says when he learned Andre Timothy Jackson had been charged in the murder, he said, "I couldn't believe it."
The man says he met him while at the Salvation Army Harbor Light center. The two were in a veterans program and had served as Marines at different times in Iraq.
Jackson was in the United States Marine Corps and was discharged in 2011, according to HPD.
Another man was also previously charged and released in the murder.
The horrifying situation happened Tuesday afternoon outside Richard Guerra's home.
Guerra said he was inside the kitchen eating when he heard a little boy cry out.
"First. He goes 'Ah!' He screams and the first scream didn't catch my attention. The second one did. I hear him saying, 'Take everything please. Don't kill me please,'" said Guerra. "I came out the front door. I walked to the back. The black dude had him pinned down against the fence. When he seen me, he let him go. He ran off. I walked up to the kid. He talked to me like normal but he was scared. He told me, 'I'm alright. I want to go home. I want to go home.'"
It was difficult for Guerra to recall what happened next.
The man said the little boy tried to walk away but suddenly collapsed on the ground.
It was only then that Guerra realized the boy had been stabbed by the attacker. Guerra said he witnessed stab wounds to the boy's chest and arm.
"He fell face first. That's when I got freaked out so I turned him over and that's when I seen the blood," said Guerra. "That's when I started panicking."
Guerra explained he tried to stop traffic, hoping someone could help.
A man across the street called 911.
Guerra saw a cop pull into a nearby gas station and flagged him over to help. Guerra decided next to go after the killer.
PHOTOS: Boy stabbed in horrific killing
"I seen him in the street running. I went after him with my van. I tried to run him over but he was fast enough that he got to Main Street. He crossed over the light rail tracks and ran along the side and went on to Winnie," said Guerra. "I sure did want to kill him. I seen what he did. That was a little kid. That's not right."
Guerra said the killer wanted to rob Josue.
"It was to rob him. He didn't have nothing but his backpack," said Guerra. "I'm pretty sure he already wasted his lunch money. He was coming home from school."
Omar Garza lives just down the block. Just moments after the stabbing, Garza said a man raced by his house.
"I was barely warming up the charcoal. That's when this guy. He runs by. He looks at me. He keeps looking back. He's just running. He's nervous," said Garza. "He's just a little boy. I had to help out. No one seen him. It was all on me."
Garza told police what he had witnessed. He later picked a 31-year old man - the first suspect in the case - out of a police lineup.