The stepmother of Gannon Stauch, an 11-year-old who has been missing for five weeks in Colorado Springs, was arrested in South Carolina and charged with first-degree murder, Colorado authorities confirmed Monday.

Letecia Stauch, who was the last person to see the boy, faces several other charges including child abuse resulting in death, tampering with a body, and tampering with physical evidence.

The El Paso County Sheriff’s Office, which has been leading the search for the 11 year old, announced the charges at a press conference in Colorado Springs on Monday.

“As you can see by the arrest, we no longer believe that Gannon is alive,” Lt. Mitch Mihalko said.

Sheriff Bill Elder said that investigators will remain “steadfast and diligent until the final prosecution.” Letecia Stauch is being held without bond and has been extradited to Colorado, he added.

“Justice will be served because my boy does not deserve this,” said Gannon’s biological mother, Landen Hiott, standing alongside the boy’s father, Albert Stauch, at the press conference. “She will pay 100 percent for this thing that she did,” Hiott added, “because I want to live on this Earth knowing that justice will be served for my little boy.”

Gannon’s father said in a statement that was read aloud during the press conference, “The person who committed this heinous, horrible crime is one that I gave more to anyone else on this planet, and that is a burden that I will carry with me for a very long time.”

Letecia initially reported Gannon missing, telling authorities that he walked over to a friend’s house at 3:15 p.m. on Jan. 27 and never returned. She told El Paso County police that she believed the child had been abducted.

But a video provided by the family’s neighbor in Colorado Springs called her story into question, as it appeared to show the child entering his stepmother’s truck and leaving with her on the day he disappeared. The video apparently shows Stauch returning home without her stepson.

It was later revealed that he did not attend school that Monday.

In February, El Paso County Sheriff’s Office spokesperson Sgt. Deborah Mynatt cast doubt on Gannon’s alleged kidnapping, saying, “We are really trying to also ensure that the community knows if there was a threat of some sort of public safety statement, if there was an abduction of some sort, if that information was revealed to us… we would absolutely put that out,” according to People magazine.

Landen Hiott said in a video statement released earlier in February, “I don’t even have answers for my feelings, other than I’m afraid,” adding, “Afraid that I will never hear his voice, that I will never hear him run and say, ‘Mommy!,’ that I will never hear those corny jokes that he always tells. I am afraid I will never see that again or hear it.”