A Maine woman who said her struggles with gender identity pushed her to stab her two parents to death when she was 17 was sentenced Tuesday to 40 years in prison.

According to her attorney, Andrea Balcer, now 20, was transitioning from male to female when she killed Alice and Antonio Balcer, both 47, on Halloween 2016. WGME reported that she also killed the family chihuahua because it wouldn’t stop barking.

The Kennebec Journal and Morning Sentinel reported that Andrea was raised as a male, though she felt she was a woman since age 3 or 4. On the morning of the murders, Andrea told a 911 dispatcher she “just snapped,” later telling  chief forensic psychologist Debra Baeder that her father made a transphobic remark a day earlier.

Andrea told Baeder, “I killed my parents because they suppressed who I was for so long and forced me to be someone I wasn’t for so many years. I snapped.”

WGME reported that Andrea appeared cold and callous while recalling how she killed her parents—and even laughed about it on a few instances.

Alice was found dead in the bedroom, lying face down with a stab wound in her back. Antonio was located in the kitchen and had 13 stab wounds to his chest and torso, the Journal and Morning Sentinel reported.

“I made a terrible mistake, one that cost the lives of the two people that gave me life and raised me,” Balcer said in September after pleading guilty. “I am only here to ask for one thing: That is the forgiveness of my family.”

Days before agreeing to plead guilty, Andrea accused of her mother of molesting her and claimed her father physically and emotionally abused during a jailhouse interview with the local news outlet. Christopher Balcer, Andrea’s older brother who was home at the time of the slayings, denied Andrea’s allegations.

Christopher said of his murderous sibling, “As far as I’m concerned, he died that night to me. ‘Hatred’ is a strong word, but it’s also an accurate one. That’s all that’s left.”

[Featured image: Andrea Balcer/Kennebec County jail]