The stepmother of a missing 11-year-old Colorado boy has been arrested on suspicion of first-degree murder, authorities said Monday.

Letecia “Tecia” Stauch was taken into custody without incident earlier Monday in Myrtle Beach, South Carolina, and will be extradited to Colorado to face charges for allegedly killing stepson Gannon Stauch, El Paso County Sheriff Bill Elder told reporters during a press conference.

In addition to first-degree murder, Stauch, who remains held in South Carolina without bond, will face charges of child abuse resulting in death, tampering with a deceased body and tampering with evidence.

Elder said the boy’s body has not yet been found, but a sheriff’s lieutenant said information has been obtained that should narrow the ongoing search.

“We will not stop and this investigation has just begun,” Elder told reporters.

Gannon was last seen leaving his Colorado Springs home on Jan. 27 when he left to visit a friend, his stepmother had previously told authorities. The boy was initially characterized as a runaway, but investigators later upgraded his disappearance to an endangered missing person’s case after learning he relied on prescribed medication, El Paso County Sgt. Deborah Mynatt told The Post in February.

Investigators did not provide details as to what led to Monday’s development and an arrest affidavit in the case is sealed, authorities told reporters. Elder and other officials also declined to answer questions.

The boy’s biological mother, Landen Hiott, said she was “astounded by the amount of love” shown during the search for Gannon while calling for justice and privacy from the media.

“I never thought I’d be standing here,” she told reporters through tears. “It’s a nightmare.”

In a statement read to reporters, the boy’s father, Al Stauch, said his “little boy is not coming home,” adding that they will never play Nintendo again or enjoy tacos together on Tuesdays.

“How can I question God for bringing Gannon home to him?” Stauch said in a written statement read by a sheriff’s office spokesperson. “Because Gannon believed in God and I will never stop believing.”

A spokeswoman for the El Paso County Sheriff’s Office had previously declined to comment on a report that a neighbor’s home surveillance system caught Letecia Stauch and her stepson getting into a red truck before she returned hours later without the boy.

The footage proved Letecia Stauch was being untruthful with police, her neighbor told the Denver Post.

“I mean, it blows her story out of the water,” Roderrick Drayton, 49, told the newspaper. “She came back at 2:19 without him.”

Al Stauch was out of town for training with the National Guard when Gannon vanished, he told KOAA.