COMMERCE CITY (KWGN) — A Lakewood cop who was found dead in a murder-suicide was about to be arrested for allegedly abusing his three-month old daughter, according to Commerce City police. William O'Shell and his wife, Tiffany O'Shell, who was a former Lakewood police officer, were found shot to death inside their home Monday night on the 11500 block of River Run Parkway in Commerce City.

Police say it was 6:15 p.m. on Monday when they first got the call about two people dead inside the home. The call came from Tiffany's mother.

Tiffany O'Shell was hired by the Lakewood Police in 2006, but resigned a year later. O'Shell was a Lakewood police officer hired in 2005 and assigned to the patrol division.

At a news conference in Commerce City on Tuesday, police made a stunning announcement: William O'Shell was the prime suspect in a child abuse case involving his own 3-month-old daughter. Sgt. Joe Sandoval told reporters, "The child suffered what we consider to be serious bodily injury. It was nothing life threatening, but serious enough to where it involved fractures, breaks and things of that nature."

Sandoval says it was June 17th when the couple first brought the baby to a hospital. "Our investigators responded directly to the hospital to start interviewing doctors and family members who were there to try to make their determination about who had cared for the child, " he said.

The investigation focused on four people: William O'Shell, Tiffany O'Shell and two relatives who had cared for the baby. But soon, everyone but William was ruled out as a suspect and police say they were just about ready to make the arrest. "The case was being built. We were getting very close to presenting the case to the D.A.'s office," said Sandoval.

Now, instead of a child abuse case, police are investigating a murder-suicide, and they say until the autopsy is completed, they still don't know who killed who.

Police say the couple's baby is expected to make a full recovery from her injuries. She is now in a foster home and in the custody of Adams County Social Services.