CNN:

Police in a Dallas, Texas, suburb indicated Wednesday that the town's mayor likely killed her daughter before turning the weapon on herself.

The Dallas County Medical Examiner's Officer ruled Wednesday that the mayor's death was a suicide and her daughter's a homicide.

Coppell Mayor Jayne Peters, 55, and her daughter Mary Corinne Peters, 19, were found dead Tuesday evening by officers who had been sent to check on the family's welfare.

CNN affiliate KTXA reported from a police briefing that officers found an envelope containing a note and a key to the two-story house on the front door and three other notes inside the house. Thomas said that "it appeared to me there had been some thought behind all of this."

The Dallas Morning News said the outside note warned officers of what they would find inside. Police told the News the notes gave no clues as to what led to the shooting but rather provided instructions on, among other things, how to care for the family's pets. Two dogs were found in the house, the newspaper reported.