FORT WORTH (CBSDFW.COM/AP) — The brother of a Fort Worth man accused of killing an inmate in a jail cell says his brother shouldn’t have been housed with another person because he’s diagnosed with schizophrenia and has hallucinations.

The Fort Worth Star-Telegram reports that Brandon Flores doesn’t believe that his 43-year-old brother David Flores fatally attacked 76-year-old Clinton Don Simpson because Simpson is an alleged child molester or because of his age.

Clinton Don Simpson of Keller (photo credit: CBS 11 News)

Brandon Flores says his brother’s mental illness likely escalated in Tarrant County Jail after feeling vulnerable and alone.

Simpson was pronounced dead last week, shortly after the attack. Simpson was charged with molesting children attending parties at a miniature-train complex he built in his yard.

Brandon Flores says David Flores had never been violent until October, when he was accused of hitting an elderly employee at a store.