Three groups, two-probe (2PG), three-probe (3PG), and control (CG), performed a mock crime. 2PG and 3PG stole two and three items, respectively, after a baseline "truth block"; the CG stole nothing. Subjects all completed a second "lie block" after the mock crime. There were four stimuli in truth and lie blocks: truth probe (TP), truth irrelevant (TI), lie probe (LP), and lie irrelevant (LI). Stolen items were probes; other items were irrelevants. Spatial-temporal PCA was applied. For the 2PG, subjects' frontal-central component amplitudes in the 520-644-ms temporal component were significantly more positive for LP than for LI stimulus. Individually, 12 of 14 subjects (far better detection than results [72% hits] with non-PCA analyses methods) in the 2PG were detected, with a false positive rate of 4 of 14 in the CG. No difference between LP and LI was found in 3PG data. In summary, spatial-temporal PCA improves detection of concealed information.