Marilou Danley, 62, reportedly lived with Stephen Paddock at a home in Mesquite, Nevada.
Danley is currently out of the country.
The sheriff did not release further details about Danley, but said they will try to speak with her when she is back in the United States.
Danley posted photos to Facebook from the Mandalay Bay Resort and Casino three years ago.
We will continue to bring you more on this developing story as it becomes available.