Fredrick Matthew Lochridge, 15, was arrested Sunday in the murder of his 10-year-old sister, Isabella Heffernan, after she was reported missing by her family and was later found behind her home in Fountain.
According to an arrest affidavit released this afternoon, Lochridge, who was initially said to be 16 years old but is actually 15, admitted to shooting Heffernan with a .22 caliber rifle at around 3am on Sunday.