The court heard that on 19 December the Colorado Springs Police Department responded to a 911 call reporting a burglary at a Colorado residence at 00:29 local time (06:29 GMT).

When officers arrived at the defendant’s address, they found two dead children and a third with a serious injury to her neck. She was taken to hospital.

Live rounds and spent cartridges were found in a closet and a “blood-stained handgun” was discovered on the floor of the bedroom, the prosecutor added.

A blood-stained knife was also found in the living room of the property, Mr Smith added.

The court heard that DNA tests were carried out on the knife and the gun and revealed the presence of mixed profiles matching the children and Ms Singler.

Mr Smith added: “Two empty bottles of sleeping tablets were also found and there were no signs of a break-in.”

The court heard the third child required emergency surgery, but survived.

Mr Smith said Ms Singler blamed her husband for the attack, but it was found he had been driving a “GPS-tracked truck” in Denver, giving what the prosecutor described as a “complete and verifiable alibi”.

In the days that followed, the third child, who was not named in court, was moved into foster care after her emergency surgery.

On Christmas Day, she told her foster carer that Ms Singler had been responsible for the attack and had asked her to lie to police, Mr Smith said.

The prosecutor said the girl was interviewed by police on 26 December, during which time she recounted how the attack had unfolded after the defendant guided all three children into their bedroom.

“The defendant told her that God was telling her to do it, and that the children’s father would take them away,” Mr Smith said.

The police investigation then led to a warrant being issued by Fourth Judicial District Court in El Paso County, Colorado, for Ms Singler’s arrest.

Mr Smith said Ms Singler was arrested in the Chelsea area of west London on 30 December.

Ms Singler’s defence barrister Edward Fitzgerald told the court she “denies she is responsible for the death of her two young children and the attempted murder of her third child”.

“She is innocent,” he said.

Members of Ms Singler’s family joined via a video link, as did the Colorado State prosecutor and officials from the US Department of Justice (DoJ).

The extradition hearing continues.