The detected submarine was tracked by sonar, it was easy once they knew where to look.
We detected the submarine long before it observed us.
I detected his rhythmic breathing within minutes.
Any denial would be immediately detected as a lie, anyway.
I could commonly hear the splash of the water when he came up, and so also detected him.
The minute he detected something more than a platonic relationship, it was going to be good-by friendship.
Dean detected a hint of a blush from his card-playing partner.