True story of married couple who disappeared after being left behind on diving trip and never seen again

A couple were never seen again after they became stranded while out on a diving trip.

Their story was adapted into a film, tilted Open Water - you can see the trailer here:

Eileen and Tom Lonergan, from Baton Rouge, Louisiana, signed up for a day trip to explore the Great Barrier Reef on 25 January 1998 after stopping at Australia on their way home from a holiday in Fiji and Tuvalu.

Eileen, 28, was an experience scuba diver and had convinced her 34-year-old husband to take up the hobby with a trip to the famous coral reef an ideal place to visit.

The couple, alongside 24 other passengers, boarded a boat called Outer Edge, manned by skipper Geoffrey 'Jack' Nairn and travelled 60km off the coast where the underwater adventure began.

Once the diving was done for the day, a headcount was conducted and the boat returned to the mainland.

QLD Police

However, something clearly went wrong and it later transpired the couple were not on board the Outer Edge when it headed back.

Two days later, a bag belonging to the married couple was discovered on the vessel.

This led to the suggestion that Eileen and Tom must have resurfaced from the last of the three dives to find the boat had left without them.

In the days that followed, a wide-spread air and sea search took place but, tragically, the couple were never found.

In February, a month after their disappearance, a wetsuit in Eileen's size washed up on the northern Queensland shore with tears to it that experts said would have been a result of contact with coral.

After that, dive jackets, tanks and one of Eileen's fins turned up as well.

According to reports, nothing suggested their lives had come to a violent end (in the film Open Water, the couple are depicted as victims of a shark attack).

Months later, a fisherman found a dive slate 160km away which read: "[Mo]nday Jan 26; 1998 08am.

Tom and Eileen Lonergan

"To anyone [who] can help us: We have been abandoned on A[gin]court Reef by MV Outer Edge 25 Jan 98 3pm. Please help us [come] to rescue us before we die. Help!!!"

The date on the slate shows that the couple were alive for at least a day.

The Outer Edge skipper was charged with manslaughter and explained how he had ordered a crew member to carry out the count, and the numbers had become confused because two passengers had jumped into the water halfway through.

He was later found not guilty by a jury. His company pleaded guilty to negligence and went out of business.