Zuberi Sharp, a 24-year-old from Newbury Park, allegedly attacked his 15-year-old brother Zayde Keohohou inside a home in the 400 block of Jeanne Court last Thursday around 8 p.m., according to the Ventura County Sheriff's Office.
He was later taken into custody on the Newbury Park High School football field, about half a mile away from the home where the attack allegedly happened.
He was naked at the time of the arrest.
The judge overseeing Sharp's case did not allow cameras in the courtroom Monday.
During his court appearance, which lasted about a minute, the judge ordered a mental health evaluation for Sharp before he's arraigned.
Sharp is due back in court on January 2.
Last Friday, Keohohou's family members gathered for a brief public statement, saying in part: "We appreciate the outpouring of love, aloha, support and prayers from friends and ohanas and this wonderful community."
Keohohou was found with blunt force trauma to the head, sheriff's officials said. It was not immediately known what weapon was used, but a spokesperson from the Ventura County Sheriff's Department said it was possibly an ax.
Keohohou died on his way to the hospital.
The motive for the brutal attack remains unknown. The investigation is ongoing.
Detectives are asking the public if anyone has video of the suspect fleeing from the scene and/or prior to being taken into custody, to upload them using this link.
Meanwhile, a GoFundMe account has been set up to help Zayde's family.
Sharp's father is currently serving time in prison for an unrelated murder.
The Ventura County District Attorney's Office confirmed to ABC7 that Zuberi Sharp, 24, is the son of Calvin Sharp, the man convicted of chasing down and killing a 6-year-old boy with a meat cleaver in Newbury Park in 2007.
During that attack, the boy's mother and a neighbor who attempted to intervene suffered serious injuries.
Calvin Sharp asserted an insanity plea but was ultimately found sane by a judge who sentenced him to life without parole, plus two additional life terms in 2012.
Family told Eyewitness News that the brothers have different fathers, and that Sharp is the father of Zuberi. Sharp isn't the father of Keohohou.