A Florida teenager has been formally charged with first degree murder in the beating death of his adoptive mother with a mason’s hammer.

A grand jury issued the indictment Tuesday, charging 19-year-old Antwan Anderson with the murder of 70-year-old Jeanette Anderson, the Palm Beach Post reported.

Police said the teen beat his mother over the head with a hammer in April because she told him to get off the phone, according to the paper, adding that Antwan found the hammer in the closet and waited until Jeanette went to bed to carry out the attack.

Antwan reportedly told his brother he was “tired” of the elderly woman, the Post reported.

When a detective asked if he regretted what he had done, Antwan replied with a smile, "No, why would I be sorry about this?" according to the Post.

Click here to read more from the Palm Beach Post.