The grief-stricken mother of the three Washington girls who were allegedly killed by their homeless father said their deaths could have been prevented if police had listened to her pleas to issue an Amber Alert when they first went missing.

Whitney Decker said she knew her daughters — Paityn, 9, Evelyn, 8, and Olivia, 5 — were in “substantial danger” when their father, Travis Decker, did not return home within a court-ordered deadline following his visitation on Friday night, The Seattle Times reported.

“As soon as he didn’t bring those girls back at 8 o’clock, she knew something was going on,” said Whitney’s attorney, Arianna Cozart.

“There should be enough concern for the police to say, ‘These children are missing, they are in substantial danger,’ even though he didn’t issue an overt threat,” Cozart added.

The lawyer alleges that Wenatchee police had wanted to issue the Amber Alert, but the local officers were told by the State Patrol that the case didn’t meet the requirements.

Instead, the State Patrol put out an Endangered Missing Persons Advisory for the three girls, which unlike an Amber Alert, does not send out cell phone alerts to the public.

Because Travis was on a scheduled visit with the girls, State Patrol argued that there was not an immediate legal presumption that the kids were kidnapped or in danger.   

Cozart, however, argued that police failed to take into account Travis’ declining mental health, including diagnoses of post-traumatic stress disorder and borderline personality disorder.

“We may never know if it could’ve meant the difference between life and death for those girls … but it could’ve made a huge difference,” she said. 

Along with the police’s alleged failure to take the case seriously, Whitney believes her children could have been saved if Travis got the help he needed as his mental health spiraled. 

Cozart said Travis, a Washington National Guard member, had been desperately seeking mental health services from Veteran Affairs and a veterans crisis line, but was allegedly offered no help and left to wallow alone. 

“This was a tragedy that could’ve been completely avoided with proper funding of mental health services for veterans,” Cozart said. 

Whitney ultimately believes that “something broke inside” Travis that caused him to do something unimaginable to their children.

The three girls were found with plastic bags over their heads and their wrists zip-tied, with the bodies located in an embankment at Rock Island Campground, about 18 miles west of the town of Leavenworth, Washington.  

Preliminary investigations indicate the girls likely died from asphyxiation.

In the days leading up to the brutal killings, Travis was seen walking around a Chelan County home appearing disorientated. 

Doorbell footage showed Travis strolling up to an unidentified home’s door and knocking on it before strangely sliding his hand up and down the surface, according to video released by the Chelan County Sheriff’s Office. 

Authorities noted the video was from before the alleged killings, but released the footage as they are the most recent images of Decker, who has yet to be found.

Police remain on the hunt for Travis, an avid outdoorsman who is believed to have undergone mountain survival training. 

“We understand that at times, he would do [geocaching], so we understand that’s a possibility that he could have scoped out this area before, put some supplies out there, and has the ability and knowledge to survive for long periods of time,” Chelan County Sheriff Mike Morrison told reporters. 

A $20,000 reward is being offered for information leading to Decker’s arrest.