Updated

A Texas woman, fighting with a friend about money, recruited a man and his teenage girlfriend to help her stage a robbery during which the trio beat and stabbed the mother of three to death, cops said.

Amy Medina, 37, was arrested in connection with the death of Lucy Bertrand, 33, who was found dead in her Texas City apartment last Thursday, KHOU11 reported. Police initially believed Bertrand died during a home invasion. But then investigators found evidence showing Medina plotted the death of her former friend.

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Lucy Bertrand was found dead in her Texas City apartment last Thursday. (Facebook)

Medina allegedly recruited Cory McCray, 19, and his teenage girlfriend -- who was not identified due to her age -- to stage a robbery during which Bertrand was killed. Medina and Bertrand were involved in a dispute about money, officials said.

Medina and McCray beat the mother with a pistol before the teen stabbed Bertrand to death, KPRC reported, citing documents.

McCray and the teen were arrested on Wednesday. Medina was already in police custody and faces a murder charge.

Medina and McCray were each being held on a $250,000 bond.