HENRICO COUNTY, Va. -- Thomas Tiller, a retired Henrico forensic detective, has been indicted by a grand jury for obstruction of justice and attempt to elude or escape police.

The charges involve a case in which his son, William Davis Tiller, was charged with the murder of his fiancee Tammy Jo Clifton.

Tiller is accused of shooting Clifton inside her Engel Road home, in Henrico's near West End, on November 23, 2016.

"As a parent I know there's a lot you're willing to do for your children, but at one point, there's got to be something inside that says it's not right," Tammy’s sister Sherry Clifton said.

For the first time since her sister's tragic death, Sherry spoke about Tammy and her relationship with her accused killer.

"The girl came over and said, ‘He shot my mommy,’" Sherry said, referring to her niece.

Tiller's father Thomas, a former Henrico Police detective, is accused, Crime Insider sources said, of tampering with evidence at the crime scene that night.

"For someone to spend so many years fighting for the good, to try and do what's right and know right from wrong to completely try to evade and hide it and cover it up,” Sherry said. “It just blows me away."

She said she had a feeling the charges were coming.

Crime Insider sources said the night of the murder, William Tiller called his dad and not 911.

Sources said Tammy was shot while her two children were in the house, leaving images of domestic violence that still haunt them to this day.

"They always ask, ‘Why? Why did he do it and why did it happen?’" Sherry said, referring to her niece and nephew.

At last check, Thomas Tiller has not been officially booked on the indictments yet.

William Tiller has another court appearance at the end of April.