TITUSVILLE, Fla. (CBSDFW.COM/AP) — A Florida sheriff says a 21-year-old Texas man told an undercover deputy he wanted to “rape, kill, and cannibalize” a child.

Brevard County Sheriff Wayne Ivey told news outlets Tuesday that Alexander Nathan Barter posted an online ad about trying “necrophilia and cannibalism and see how it feels to take a life.” Ivey says an undercover deputy who also works for U.S. Immigration and Customs Enforcement saw it and offered Barter a child.

Investigators say deputies then drove to Joaquin, a Shelby County town of less than 1,000 people near the Texas-Louisiana line, and met with Barter.

“This is not somebody that was roll playing. This is not somebody that was just “talking” online,” Sheriff Ivey said. “This is somebody that actually, when he was arrested, showed up with a knife and bags to take the body parts out.”

Ivey says Barter was arrested on charges including criminal attempt of capital murder and confessed before allegedly thanking the agents for stopping him because he couldn’t stop himself.

The Sheriff said Barter is, “One of the most sick, disgusting and demented people I believe I have ever had the unfortunate nature to be involved with.”

It’s unclear if Barter has a lawyer.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)