What does 'false positive' mean? That it thinks it is someone else, or that it thinks it is a target of an investigation?
When the actual is negative but the inference is positive, rate of that.
This is a very handy guide: https://en.wikipedia.org/wiki/Confusion_matrix
False positive would, in this case, mean wrongly identifying an unrelated person a the search target.
When the actual is negative but the inference is positive, rate of that.
This is a very handy guide: https://en.wikipedia.org/wiki/Confusion_matrix