A judge had ordered three Colorado children to spend Christmas with their father, before his ex-wife allegedly violated the custody decree and killed two of the kids, court records show.

Kimberlee Singler, a 35-year-old Colorado Springs mother of three, was taken into custody over the weekend in the United Kingdom and held in connection to the killings of her younger daughter, 9, and son, 7, officials said.

Police on Dec. 19 responded to an early morning 911 call about a burglary at Singler’s condo where they found the two dead children and took their mother and 11-year-old sister to the hospital. Police eventually said there was no burglary and issued an arrest warrant for Singler, who had fled the jurisdiction.

Singler and her ex-husband, 38-year-old Kevin John Wentz, had been locked in a years-long court battle over custodial issues.

Singler had recently accused Wentz of pulling a knife on her and the allegations briefly cost the father time with their children. The court eventually ruled that Wentz didn’t represent a threat to his children before lifting the restrictions against him spending time with them.

The court ordered “makeup parenting time,” with children set to be tuned over to Wentz at the Stetson Hills Division station of the Colorado Springs police at 9 a.m. on Dec. 16 before going back to Singler at noon Dec. 31 at the Greeley Police Department, court records showed.

It appears Singler did not show up with the children, because Wentz went to court on Dec. 17 asking for emergency action and a “law enforcement assist to enforce parenting time,” Larimer County court records showed. A hearing was then set for Dec. 20, which turned out to be a day after the slayings.

That Dec. 20 hearing was called off with the court expressing “condolences about the recent occurrences for the parties and their families,” according to the records.

Colorado Springs police spokesman Ira Cronin declined to say anything further on the matter.

“I’m sorry but right now CSPD is declining to comment on any of the custody issues between Mr. Wentz and Ms. Singler, as it is directly tied to our investigation,” he said.

For years, it appeared Singler represented herself in family court and her former attorney declined comment on Tuesday.

Wentz’s attorney could not be reached for comment on Tuesday and Wednesday.

The ruling to restore Wentz’s rights to see his children appeared to include a request by the court for both parents to undergo polygraph tests about the knife allegation.

Singler declined to take the polygraph, records showed, but the court said that refusal played no role in the ruling to reinstate Wentz’s parenting rights.

‘The court cannot rely on the presented polygraph examination in this matter,” said court records. “Therefore the court will strike the polygraph evidence from the record.”

Jennifer Hendricks, who teaches family law at the University of Colorado, said she was struck by the highly unusual court request.

“They’re (polygraph tests) inadmissible in most places generally and including in Colorado,” Hendricks said. “The particularly strange thing about this is the judge orders it and then rules it inadmissible.”

The practice of exchanging children in the presence of law enforcement might sound extreme but Greeley police spokesperson Kent Keller said it’s been an increasingly used, effective tool by courts to keep hostile parents on their best behavior.

“These (exchanges of children) would usually happen in fast food parking lots and at the parent’s homes,” Keller said. “But I feel having the exchanges at a police department is the best way to ensure that the guardians and kids are safe and the exchange goes smooth with the knowledge that officers are mere feet away.”