A Honduran man accused of decapitating his mother in North Carolina was in the United States illegally, federal officials said Tuesday. 

Immigration and Customs Enforcement spokesman Bryan Cox told FOX 46 Charlotte that the agency had issued a detainer for the suspect, identified as 18-year-old Oliver Funes. 

The suspect's full name was not immediately clear. Cox said Federal records list his name as Oliver Funes Machado. However, local court records listed the suspect's name as Oliver Funes Machada, public defender C. Boyd Sturges III said.

Franklin County Chief Sheriff's Deputy Terry Wright gave the mother's name as Yesenia Beatriz Funez Machado, citing a spelling given to authorities by her 14-year-old son.

Prosecutors allege that the suspect decapitated his mother and then walked out the front door of her house holding her head in his hand while wielding a knife in the other. He was charged with first-degree murder Monday.

WNCN, citing a search warrant application filed Tuesday, reported that the suspect told investigators that he stabbed his mother "like 8 times" and said he killed her "because I felt like it."

District Attorney Mike Waters said officials were seeking a mental evaluation of the suspect. Sturges said he spoke with him for an hour in the Franklin County jail.

"It does appear there's some substantial mental health issues involved in this case," Sturges said. "I'm not a doctor, so I can't really elaborate. He's a pretty profoundly disturbed young man."

Waters said due to the suspect's apparent mental state, "this is something that's going to take weeks and months for us to get some answers as to why this happened."

Waters said the suspect was being transferred to Central Prison in Raleigh. His next court appearance is scheduled for March 14.

Two young girls in the home were not hurt. A fourth child was in school when the attack occurred. Deputies were searching the home hours after the body was discovered.

Neighbor Randy Mullins, who was leaving his house minutes after the first deputy arrived, said he saw the woman's head lying in the front yard about five feet in front of the porch. The deputy appeared to have just handcuffed the suspect and seemed rattled when Mullins approached to ask if he needed help.

"You could see in his face he had a lot of concern. I'm not saying he was scared, but you could tell he was concerned," Mullins said of the deputy. Mullins then went back to his house across the street and told his 91-year-old mother to stay inside. He said a half-dozen more law enforcement vehicles arrived within minutes, and a deputy covered the woman's head.

"I couldn't believe it. Things like that don't happen," said the 59-year-old Mullins, who has lived in the neighborhood for 25 years. "You can't believe somebody would do that. You hear about that, but it never happens across the street from you."

Mullins said the family had moved to the neighborhood sometime around June. He didn't know them well, but he and his mother said they seemed friendly.

"If they were outside, they always waved at you," said Clearsy Mullins.

Randy Mullins said the suspect appeared placid as he sat handcuffed and the deputy was kneeling down to comfort the two younger children.

"He was sitting there like he didn't have a care in the world. He didn't appear to be upset. He didn't appear to be crying."

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The Associated Press contributed to this report.