Saturday evening, Spectrum News spoke with the sister of the Guilderland mother involved in a murder-suicide. 

Guilderland Police say 27-year-old Caitlin Melville fatally shot her 5-year-old daughter, before then shooting herself. 

Michelle Melville says her sister Caitlin has long battled severe mental health issues. She believes Caitlin was not thinking clearly and her judgement was clouded. 

Michelle also said Caitlin's longtime boyfriend died a week ago, adding that he was a father figure to the 5-year-old.

Friday, the bodies of Caitlin and her 5-year-old daughter were found inside of a home on Schoolhouse Road. 

Michelle says her family is shocked. She hopes by sharing her story, someone experiencing mental health issues could reach out for help. 

Michelle also shared with us how she will remember her sister and her niece. She said this tragedy never should have happened. 

"If she had just said anything, anything at all. She was a good person. She was giving, she was kind, she was funny. My little boo. She was incredibly smart, incredibly funny. I still can't comprehend what was going through her mind that would make her choose this path," Michelle said.

Family members shared these photos with Spectrum News but asked us not to use the daughter’s name.