N.C. Gen. Stat. § 1-149: When verification omitted; use in criminal prosecutions.

The verification may be omitted when an admission of the truth of the allegation might subject the party to prosecution for felony. No pleading can be used in a criminal prosecution against the party as proof of a fact admitted or alleged in it. (C.C.P., s. 117; 1868-9, c. 159, s. 7; Code, s. 258; Rev., s. 493; C.S., s. 533.)