Tulsa police are responding to a home near 51st and Peoria. Police said they are investigating the discovery of a body at the home.
According to police, the woman was in her 60s and lived alone.
They said the brother went to the house to mow the yard and discovered his sister dead in the bedroom.
There are no obvious signs of trauma to the body, according to police.
They said it may be medical but they are investigating it as a homicide.
Police are waiting for the medical examiner to determine a possible cause of death.