A 13-year-old choked and beat his 8-year-old brother to death because the younger boy ate a dessert and the older one worried he would be blamed, authorities said Wednesday.

Demetrius Key was arrested on first-degree murder. The boys' mother, Tangela Key, told police she was visiting a cousin nearby and left him in charge of Levares Key and other younger siblings Saturday.

A neighbor told investigators she heard four loud bangs, followed by 10 minutes of quiet and then more commotion, according to an Orange County Sheriff's Office news release.

Demetrius Key went to the cousin's house and told his mother his brother was "passed out," the sheriff's office said. The younger boy was pronounced dead at a hospital.

Demetrius Key initially said he hit his brother with a metal shelf support, investigators said. After investigators searched the house, he said he used a broom handle, the sheriff's office said.

He then told the detective he punched the boy, choked him and banged his head on the floor, according to an affidavit.

"Demetrius offered that Levares upset him by eating a dessert that (he) was not to have eaten," Detective Appling Wells wrote. "He also advised Levares upset him by picking a scab and causing it to bleed.

"Demetrius said he feared Levares would blame both circumstances on him and tell his mother he had struck him and eaten the dessert."

The sheriff's office would not say what the dessert was.

Orange County Medical Examiner Dr. Jan Garavaglia ruled the death a homicide from closed head injuries.

Tangela Key does not have a listed telephone number. The sheriff's office did not immediately know whether Demetrius Key had an attorney.