JACKSONVILLE, Fla. -- A 12-year-old boy fatally shot himself in late July while playing with a loaded weapon, prosecutors claimed for the first time on Monday.

The state's theory was contained in court papers by Assistant State Attorney Bernie de la Rionda in the case of a man charged with manslaughter for allegedly providing the gun that contributed to the death of Anthony "Tony" Youmans.

"Anthony tragically shot himself in the head," the prosecutor wrote in a document filed with the judge in the case.

However, Youmans' family told Channel 4 it's not satisfied with the investigation into the shooting death of their 12-year-old son.

"It's hard. Everything is so hard about it. I mean, we just get through it one day at a time," said Youmans' mother Kelly Kidd.

She said Monday was harder than most days.

"I'll never truly believe that Tony pulled that trigger. I do believe, however, that that's all the evidence they have, but I don't believe my son pulled the trigger," Kidd said.

"Only God can convince me that my son did it to himself. The evidence that they have is showing that possibly this happened. There are a lot of things up in the air. Nobody can convince me that he done it to himself," said Youmans' father, Mike Youmans.

However, Youmans' parents said they believe Derrick Glover is the man who supplied their son with a gun.

Glover, 24, was arrested July 31, the day Youmans' body was found with a gunshot to the head. Last month, a charge of manslaughter was added to the previous charge of providing a gun to a minor.

Public Defender Ann Finnell filed a motion asking Judge Charles Arnold to drop the manslaughter charge against Glover, arguing that the state could not prove that Glover's actions caused Youmans' death.

In response, de la Rionda wrote that the manslaughter charge should stand because the boy would still be alive if Glover had not sold him the gun.

"What was the defendant thinking when he sold a 12-year-old boy a loaded revolver? What did the defendant imagine Anthony Youmans would do? Didn't the defendant think that at a minimum, this child would try to shoot it?" de la Rionda wrote.

The circumstances of the boy's death have been kept a secret for months after the judge issued an order that prevented public disclosure of many public records after his lawyer contended that Glover could not get a fair trial because of the amount of media coverage.

Because of a gag order in the case, prosecutors and defense attorneys will not discuss the case.

Police arrested Glover the day a search party found the boy's body in a wooded lot in front of the apartment where Glover lived. His body was found two days after he was reported missing on July 29.

Court documents also shed light on the case the state is likely to make against Glover:

"A child that was with Anthony Youmans during the shooting brought the firearm back to the defendant ... defendant took the firearm and told the child not to tell anyone about what happened."

Channel 4 also obtained dozens of images of guns that police said were on the computer seized during a search of Glover's home. One of those images is of a silver revolver similar to the one investigators believe Glover sold to Youmans.

Arnold will hear arguments about the manslaughter charge on Dec. 13 and Glover's trial is expected in late January.