A tainted witness falls into one or both of the two categories hereunder listed: (1) A witness who is an accomplice in the crime charged. (2) A witness who, by the evidence he gives, may and could be regarded as having some purpose of his own to serve. Rasheed Olaiya v. The State (2010) Vol. 180 LRCN 1-197 p.34; The State v. Dominic Okoro & Ors (1974) 2 SC 73 at 82; Ishola v. The State (1978) 9-10 SC 73 at 100 .
— N.S. Ngwuta, JSC. Odogwu v State (2013) – SC.122/2009