Twin brothers have been accused of sexually assaulting a teenage girl in west Harris County.

Isaac and Isaiah Gates, 19, were charged with sex assault of a child.

The brothers are accused of taking a 16-year-old girl behind a business in the 14700 block of Memorial Drive on Nov. 28 and taking turns raping her, according to court documents.

While one twin sexually assaulted the girl, the other served as a lookout, the documents said, and then the twins switched roles.

The girl said she initially agreed to have sex with the twins behind the business but changed her mind. She said that's when they began raping her.

Houston police said Isaiah Gates has been arrested, but Isaac remains on the loose.

Anyone with information about Isaac Gates' whereabouts is asked to call Crime Stoppers at 713-222-TIPS.