DALLAS (AP) — A Dallas man who was under investigation by state authorities for abusing a young boy has been arrested and charged with capital murder in the death of the boy's brother.

Twenty-seven-year-old Brandon Gordy was being held Wednesday in the Dallas County jail.

An arrest warrant obtained by The Dallas Morning News shows he's accused of fatally beating his girlfriend's 4-year-old son, Darwin Delgado.

Gordy claimed the child fell in a bathtub last week but a medical examiner said the injuries were consistent with blunt force trauma.

The warrant indicates state Child Protective Services had an open case on Gordy relating to the abuse of Darwin's 3-year-old brother.

A lawyer for Gordy could not be reached for comment.

Officials have been working to improve CPS operations in light of high turnover among case workers and other problems.