The Texas Court of Criminal Appeals denied one of death row inmate Robert Roberson’s final appeals on Friday, declining to halt his Oct. 17 execution and again rejecting his long-standing claim of innocence and argument that his conviction was based on a now-debunked shaken baby syndrome diagnosis.

Roberson, who was convicted of capital murder in 2003 for the death of his ailing 2-year-old daughter, Nikki Curtis, has maintained his innocence over 20 years on death row.

He has argued that his conviction was based on a flawed shaken baby syndrome diagnosis given to his daughter, which presumed abuse on his part and did not consider her severe illness before her death.