By Jonathan Kaminsky

(Reuters) - An Alabama woman was charged for trying to enlist a Facebook friend, who in fact was her aunt posing as a man, to kill her family, police and prosecutors said on Wednesday.

Marissa Williams, 19, faces 10 years to life in prison if convicted on one count of solicitation for murder, a class-A felony, for her alleged plot to kill several relatives and even a family pet.

Police said Williams had in April moved in with her aunt's family in the western Alabama community of Fosters, where she started to meet men online and invite them to the house.

Frustrated by this behavior, her aunt created a Facebook alter ego, Tre 'Topdog' Ellis, to befriend her niece, said Lieutenant Andy Norris, spokesman for the Tuscaloosa County Sheriff's Office.

Williams began chatting online with the fictional Ellis late last month, inviting him over and offering to have sex with him in exchange for covering her $50 cellphone bill, Norris said.

At one point, she told Ellis that she was sick of her family and asked him to shoot dead her aunt, her aunt's fiancée, Williams' cousin and the family dog and to run away with him, Norris said.

Upon reading the request, the aunt contacted the sheriff's office. Williams admitted to police she had asked her Facebook friend for the favor, but said she did not intend to actually have anyone killed, Norris said.

Norris said Williams' her approach to enlisting a hitman was not typical.

"Usually they try to get a friend or an acquaintance to do it, someone they can trust," he said. "This isn't normal behavior."

Williams was arrested on Tuesday and is in jail in lieu of posting $30,000 bond. She is due in court later this week, a Tuscaloosa County District Attorney's Office spokesman said, adding there is no record of her yet having retained an attorney.

(Reporting by Jonathan Kaminsky, editing by G Crosse)