TAMPA (CBSMiami/AP) — A Florida woman was sentenced to life in prison after she was convicted of killing her mother and stepfather.

The jury rejected her claims of insanity.

The verdict was returned early Saturday by jurors after 12 hours of deliberations in the case of 25-year-old Nicole Nachtman. A Hillsborough County judge immediately sentenced Nachtman to life without parole.

The Tampa Bay Times reports that Nachtman was convicted of fatally shooting 56-year-old Myriam Dienes, her mother, and 67-year-old Robert Dienes in August 2015. The trial lasted two weeks.

Several witnesses testified that Nachtman had signs of mental illness and that she suffered emotional abuse by her mother. But prosecutors put on evidence that Nachtman knew exactly what she had done, including a confession to her half-brother.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)