A Colorado woman accused of killing two of her children during a custody dispute with her ex-partner has been extradited to the U.S. about two years after was arrested in U.K., authorities said.

Kimberlee Singler, 37, was returned to the U.S. on Dec. 23 and is currently being held in custody in Colorado, according to Colorado's 4th Judicial District Attorney's Office. Singler faces seven counts, including the first-degree murders of her 9-year-old daughter and 7-year-old son in December 2023.

"Singler is accused of committing an unspeakable act — really, a reprehensible act," Colorado Springs Police Chief Adrian Vazquez said at a news conference on Dec. 23. "Crimes as horrific as this are simply heart wrenching... I know that these acts have deeply impacted our community and our hearts remain with the victims."

See timeline of case: Melodee Buzzard's mother charged with murder.

Singler was arrested in late December 2023 in London just over a week after two of her young children were discovered dead at their home in Colorado Springs, authorities said. Her 11-year-old daughter sustained a "significant injury" but was taken to a hospital and survived, according to prosecutors.