DOVER, N.H. (AP) — An actor and martial arts instructor accused of killing a female University of New Hampshire student last week was upbeat and described his life as “really good” three days after the woman’s death, an acquaintance said Monday.

Seth Mazzaglia, of Dover, was charged Saturday with second-degree murder in the death of 19-year-old Elizabeth “Lizzi” Marriott, who vanished a week ago and whose body has yet to be found. He is accused of strangling or suffocating her in his apartment Tuesday night; the search for the body has been focused on Peirce Island in nearby Portsmouth.