DALLAS (Reuters) - A 14-year-old Dallas girl was charged with capital murder for drowning a 2-month-old girl on Monday, police said.

Investigators initially believed the infant and the teenager were related but later said the suspect is the daughter of a family friend, who had been caring for the baby while the baby's mother has been prison.

Child Protective Services had placed the baby in the home of the family friend shortly after her birth at the request of her mother, according to police.

Another teenager was home at the time and police said she is considered a witness. There was no lawyer listed on the arrest report for the suspect.

Police did not release names of those involved in the case or a possible motive. They said the suspect's mother was at work at the time of the drowning.

The baby's body was discovered by police who responded to an emergency call at an apartment complex, according to a news release.

(Reporting by Lisa Maria Garza; Editing by Jon Herskovitz and Eric Beech)