Aaron Trejo, 17, pleaded guilty during a scheduled status hearing, according to WSBT-TV.
Trejo was accused of stabbing 17-year-old Breana Rouhselang and their unborn baby last Dec. 8. The high school football player told police that the two had argued about the pregnancy on the night of her death, Fox 59 reported.
In charging documents obtained by Fox News, South Bend Detective Gery Mullins wrote that Trejo told him that "Breana waited too long to tell [him] about the pregnancy to get an abortion. I asked Aaron what he did about that, and he replied, ‘I took action ... I took her life.’”
Trejo told Mullins that he stabbed Rouhselang in the heart with a knife because he thought it would kill her quickly, then stuffed her body into a black plastic bag, tossed the bag into a trash bin behind a restaurant and threw her phone and the weapon into a river in Mishawaka, which is about 80 miles east of Chicago.
Trejo pleaded guilty Wednesday to charges of murder and feticide. He reportedly faces up to 80 years in prison when he is sentenced on Jan. 7, 2020.
Fox News’ Greg Norman contributed to this report.