CROWN POINT, Ind. (AP) — A 19-year-old northwest Indiana woman has been sentenced to 50 years in prison for killing her mother.

Alyssa Barrett pleaded guilty in December to first-degree murder in the death of her mother, DeCarol Deloney-Cain of Crown Point.

The body of the 54-year-old United Airlines flight attendant was found in July 2014 in the trunk of her car in a wooded area of Gary. Authorities say she died of stab wounds to the chest and head trauma.

Barrett, who was 17 at the time of the slaying, admitted to being present when it occurred and lying to investigators to cover up the crime.

Her boyfriend, 20-year-old Damarius McGriggs of Merrillville, has pleaded not guilty to first-degree murder. His trial is set to begin March 14.

Barrett must serve 75 percent of her 50-year sentence.