SAN ANTONIO -- A police officer testified Thursday that a 28-year-old woman accused of drowning her boyfriend's 3-year-old son under scalding water initially lied about how the child died.

James Foster of the San Antonio Police Department told jurors that Veronica Herrera told him on June 1, 2005, that Andrew Joshua Fox Jr. drowned in the apartment complex swimming pool where the couple lived.

"She walked away for a minute to go get a soda, came back and found the child at the bottom of the pool," Foster said. "She went into the pool and brought the child and attempted CPR."

But Foster testified that he got suspicious when he noticed that the defendant's clothing was dry.

Herrera would later confess to police that she held the child under scalding water in a bathtub and then took his body to the swimming pool in an effort to make it look like an accidental drowning, police said.

The defendant said she killed the child because she got frustrated over him repeatedly asking for his father.

Herrera's lawyer told jurors that his client is mildly retarded and has the mental capacity of a 9-year-old child.

Herrera faces life in prison if she's found guilty.