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.

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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.

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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.

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