Mother shoots dead her two children, kills family dog, sets fire to her home and commits suicide in the middle of a 'bitter' custody battle with her estranged husband

A mother who was in the middle of a divorce and bitter custody battle shot dead her two young children as they slept and then herself while setting their Pennsylvania home on fire. 

Dr Stephen Diamantoni, the Lancaster County coroner, ruled the deaths of 40-year-old Carola Arnau and her two children a murder-suicide after autopsies Wednesday morning.

He says Arnau shot her 10-year-old daughter multiple times in the head and her four-year-old son multiple times in the body before putting a bullet in her own head. She also shot the family dog.

Emergency responders who arrived the Strasburg home at 1433 Village Road at about 3.20am Tuesday found the bodies in their beds in a bedroom. Officials said several fires were deliberately set on the property using an accelerant, including inside a detached garage where Arnau's estranged husband, Miguel, had been staying. 

Miguel was not home at the time of the shootings. He had been at work from 10 the previous evening and was hysterical when he came home to find what had happened.

District Attorney Craig Stedman told reporters Tuesday that the "only small comfort" was that the children appeared to have been shot in their sleep.

"I tell people, in my job, some days are worse than others, and this is one of the worst, and certainly one of the darkest."

Miguel and Arnau were going through a bitter divorce after Carola filed on February 22, 2016, writing that their 10-year marriage was "irretrievably broken". A year later, she filed for a protection from abuse order, accusing her husband of "inappropriate contact" with their 4-year-old son - a claim that was ultimately dismissed as unfounded by Children and Youth Services. Miguel Aranu's parental rights were temporally suspended but restored on April 4 when his estranged wife withdrew the protection order.

Miguel then sued for custody of his two children and a judge issued a temporary order granting Miguel shared custody of the children every other weekend and after school until 7 pm. On April 20, he dropped his complaint, saying he and Carola wished to resolve their custody issues privately. Sadly, it ended on a bitter note.