Tomorrow I will have the pleasure of speaking with Susan Cox Powell’s parents, Judy & Chuck Cox. They lost their daughter. 28-years-old. She is GONE. And now, they have lost their 2 precious grandchildren at the hands of their own son-in-law in what we now know was a painful, violent death. I want justice. For Susan Powell and for her family. We’ll be taking your calls. For more on the case go to: HLNtv.com

Police repeatedly told Susan Cox-Powell’s parents in recent months that the arrest of her husband, Josh Powell, in connection with her disappearance was imminent, a family attorney said Tuesday.

“My clients were assured repeatedly by the West Valley Police Department that an arrest was pending, be patient,” attorney Steve Downing said on HLN’s “Nancy Grace.” “…They were told repeatedly that something was going to happen and it never did.”

Downing said Chuck and Judy Cox were told last year that Powell would be arrested by November 15, and when that didn’t happen, they were told the arrest was coming sometime this summer. He said police were “absolutely” aware that Powell’s children had made statements about their mother being in a mine or in the trunk of a car - and one had even drawn a picture of the family van with Susan in the trunk - but they still did not act.

“Assurances after assurances, the arrest never happened,” family attorney Anne Bremner told Grace.

When asked about Downing's allegations, West Valley Police Sgt. Mike Powell told HLN that “Anything specific to our actual investigation itself we are not able to release or discuss at this point. We still have an active missing person investigation and the integrity of that investigation is of the utmost importance to us.”

Susan Cox-Powell was reported missing on December 7, 2009. Josh Powell told police at the time that he took their two sons camping in the middle of the night and Susan was gone when they returned. Police have called him a suspect in her disappearance and he lost custody of the children last fall.

In a voicemail message obtained by ABC News, Powell reportedly told family members Sunday he could not live without his sons. About 20 minutes later, authorities believe he attacked the boys with a hatchet during a court-ordered visit and set his house on fire, killing all three of them.

For the latest on the Powell family tragedy, watch “Nancy Grace” tonight at 8 p.m. and 10 p.m. EST on HLN.

• A voicemail Powell recorded before killing two boys and himself: 'I am not able to live without my sons'

• Authorities say boys suffered hatchet wounds before death

• Attorney says son drew picture of missing mom in trunk

FULL POST