ARDMORE, Okla. -- An overnight shooting in Ardmore has left two people dead, and residents shocked. When police arrived on scene at the 1100 block of H Street Northwest on Tuesday night, they found one person shot to death and another critically injured.

Now they're trying to figure out the motive for what they're calling a murder/suicide.

Neighbors are in shock over an apparent murder suicide in Ardmore. Police say the shooting took place at this house around 10:30 Tuesday night. They say 37-year old Michael Walton shot his sister-in-law, 46-year old Cynthia Cooper, twice in the chest with a revolver before turning the gun on himself.

"The male subject in the front yard was deceased from a self inflicted gunshot wound. The sister was taken by medics a short distance from the residence to a nearby hospital where she later died during surgery," said Lt. Eric Hamblin of the Ardmore Police Department.

Detectives are still trying to find out what exactly happened inside the house that led to the murder suicide. They do know Cynthia Cooper went to the house to check on her sister, Walton’s wife, when she couldn’t reach her by phone.

Police say they found the husband’s body in the front yard of the house.

Police are still investigating. They tell us it could take awhile to piece this case together.

No other details are being released.

Nearby residents say their neighborhood is usually quiet, and they can't believe something like this could happen where they live.

We'll continue to update you on this.