Yoandry Montano was arrested Thursday at his home on a charge of capital murder, according to the Conroe Police Department.
On Sunday afternoon, police were dispatched to a home in 100 block of Moss Hill Lane after a two-year-old boy was found unconscious in a bathtub.
Emergency personnel administered CPR and transported the boy to Conroe Regional Medical Center Hospital. From there, the toddler was taken to Hermann Children's Hospital but died the following morning.
Detectives launched an investigation after they noticed inconsistencies in a report detailing the boy's cause of death.
Their probe led them Montano, the live-in boyfriend of the child's mother.
Montano is expected to be held at the Montgomery County Jail until a bond hearing.