Undergraduate participants who conducted a simulated police investigation were presented with either a child (6 years old) or adult (25 years old) alibi witness, who was either the son or neighbor of the participant's suspect. Replicating previous research, participants were more likely to believe the adult neighbor alibi witness than the adult son. In fact, an alibi provided by the adult son actually proved detrimental to that suspect, as participants thought the suspect was more likely to be guilty after viewing an alibi provided by the adult son. However, child-provided alibis reduced perceptions of suspect guilt, regardless of that child's relationship to the suspect. The child alibi witnesses were also viewed by the participants as more credible than the adult witnesses. Copyright © 2011 John Wiley & Sons, Ltd.