SAN ANTONIO -- A woman accused of holding her boyfriend's son under scalding water until he drowned suffers from mild mental retardation, according to her defense team.

Veronica Herrera is charged with causing injury to a child in connection with the death of 3-year-old Andrew Fox in June 2005 at an apartment she shared with her boyfriend, Andrew's father.

Suzanna Herrera testified Monday that her daughter has mental deficiencies.

"She has shown limitations and capabilities in connection with (raising) a child," her mother said through an interpreter.

After drowing the child, Herrera told police in a videotaped statement that she took Fox's body to the apartment's pool, called EMS and said he drowned in the pool.

Herrera faces a maximum of life in prison if convicted.