An electronic device has a chassis, and a printed wiring board (PWB) having a hole. A fastener is installed in the hole thereby securing the PWB to the chassis. A pair of conductive traces is formed in the PWB. A cap, being an amount of conductive glue, covers a part of the fastener and fills an electrically insulating gap between the two traces, to thereby form a conductive path that connects the two traces. A sensing circuit is coupled to the traces, to detect a change in impedance of the path and signal a tamper event alert. Other embodiments are also described and claimed.