The Texas Court of Criminal Appeals on Thursday rejected a lower court's finding that death row inmate Melissa Lucio is innocent of the 2008 death of her 2-year-old daughter.

Lucio has spent 18 years on death row after being convicted of killing her daughter, Mariah Alvarez.

But questions about Lucio's possible innocence have lingered for years, stemming from questions of whether Mariah's fatal head trauma was caused by abuse or an accidental fall down the stairs as her mother and others described.