A Eunice mother who shot her two daughters before turning the gun on herself had purchased the pistol more than a week earlier in what investigators believe was a carefully planned murder-suicide, authorities said Wednesday.

Carla Watford, 39, took the lives of 16-year-old Julia Watford and 9-year-old Jayia Watford before killing herself after setting her family’s home ablaze.

Firefighters discovered all three bodies in the master bedroom when responding to a fire at the Fourth Street residence sometime after midnight Saturday.

Investigators confirmed Wednesday that the mother had bought the .38-caliber pistol and 50 rounds of ammunition nine days before the shooting, said Brant Thompson, deputy chief with the state Fire Marshal’s Office.

“She set her plan in motion days before the actual event occurred,” he said.

The mother is suspected of hiding the weapon in a safe to which only she had access, Thompson said.

“To our knowledge, no one was aware that she had purchased that gun,” he said.

Thompson also said autopsy results confirmed the mother and two daughters all suffered at least one gunshot wound to the head.

Investigators found a hand-written document at the scene outlining the mother’s intentions, but Thompson declined to discuss the contents, other than to say it referenced “dissatisfaction with a number of things” and indicated she “seemed quite at peace with her decision.”

“One could only speculate as to her state of mind when she carried out this act,” Thompson said.

Delivering a message from Carla Watford’s family earlier this week, Eunice Police Chief Randy Fontenot described the woman as a “good mother.”

“What led her to do this, we will never know,” he said.

Thompson said fire marshal’s investigators were still in the Eunice area Wednesday conducting interviews.

“We want to know as much as we can about why this occurred,” he said.