The man who killed his girlfriend and dumped her in a field in Mathis is heading to prison.
Nigel Green pleaded guilty Tuesday morning to a murder charge and was sentenced to 40 years in prison.
Green waived his right to any appeals.
Green was initially facing life in prison without parole.
His girlfriend Carina Castellanos told police Green choked her and tried to stab her.
A few weeks later, Castellanos disappeared.
Green was arrested in July 2016.
He told investigators he killed Castellanos and led them to her body.
Castellanos would have celebrated her 29th birthday on Wednesday, her family told KZTV anchor Andy Liscano.