A man, thought to be in his 30s, and a woman were found in a critical condition near a Post Shop in Wellington overnight.
Police are going door-to-door in the suburb of Kilbirnie this morning to find out what happened to the pair, who were found about 100m apart and without physical injuries.
They were taken to hospital in a critical condition and are Wellington Hospital's Intensive Care Unit this morning.
A guard is in place on Bay Rd.
The Kilbirnie Post Shop and supermarket across the road are taped off.