Warning: This story contains some graphic details.

A Colorado man convicted of murdering his pregnant wife and two young daughters told investigators that he had been fighting with his wife about their relationship before strangling her and smothering their children.

In interviews with Colorado investigators on Feb. 18, Chris Watts, described how he killed his wife, Shanann Watts, who was 15 weeks pregnant; their 3-year-old daughter, Celeste; and their 4-year-old daughter, Bella. The Colorado Bureau of Investigation released hours of audio from the interviews on Thursday.

I didnt want to do this, but I did, he told investigators about strangling his wife in a bedroom of their Frederick home. Why couldnt I just let go?