The Weld County Sheriff's Office says Jordan Limas - who is out of jail on bond but declined to comment Monday - is facing criminally negligent homicide charges in the death of his brother, Andre Limas.

According to the affidavit, Jordan Limas told police he stole the gun. The spokesman for the Weld County Sheriff's Office, Tim Schwartz, says the gun has not been confirmed stolen, in fact, when the serial numbers are run, it doesn't come back stolen.

Investigators tell 9NEWS they believe the gun was stolen, but may not have been stolen by Jordan.

The affidavit states Jordan left the gun on the dining room table of his home. As Jordan was walking out of his bedroom he saw Andre with the gun. He tried to tell his brother the gun was not a toy, to which Andre responded "Ya right." Andre then walked toward the door where some of his friends were standing. 

Jordan told police there was a struggle to take back the gun and it went off while he had it in his hand.

"Jord, Jord, it hurts," Andre said to his brother after they realized he was shot in the chest.

He moved Andre to the front porch where others helped him call for help.

Jordan hid the gun under his bed after a family member came inside to help the injured boy, according to the affidavit.

Andre died at the hospital of his injuries a short time later.

The family says a fund has been set up at Wells Fargo Bank under "The Andre Limas Foundation." A family spokesperson says the proceeds will go toward funeral expenses.

The father of the boys, David, says Jordan loved his little brother dearly.

"He's heartbroken, as we all are," David Limas said. "We entrusted, and we do still, trust Jordan with anything that had to do with Andre - babysitting him, watching him, going to the store. He did love his little brother, definitely. With all his heart."

READ THE AFFIDAVIT HERE 

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