An American scientist who was one of the leading researchers into the Loch Ness Monster has died aged 87.

Robert Rines had been involved in the development of microwave and image scanning radar, along with ultrasound, and while the technology was primarily used in the fields of health and defence, he pioneered the use ultrasound scanning to search for the wrecks of the Titanic and the Bismarck, and in 1972 used the technique in an effort to locate Nessie.

Mr Rines claimed that the survey of Loch Ness produced evidence that there was a creature in the Highland loch, and that it was probably a Pleiosaur, an extinct aquatic dinosaur.

From the early 1970s he came to Scotland regularly after he believed he saw the creature from the banks of the loch. His 1972 survey produced an image that seemed to be of a flipper, another from two years later seemed to show the head and neck of a creature.

Publication of the images, particularly the close up of the fin, led to the Loch Ness monster being given the scientific name Nessiteras Rhombopteryx (Greek for "The Ness monster with diamond-shaped fin). Many experts were convinced that the images were proof of the existence of Nessie, and were not hoaxes.

However, the images were not without controversy, some claiming that the fin image was simply the fin of a fish, and the head and neck shot was of a tree stump, and that other images of a creature's fin had been artificially adjusted to appear more convincing.

Later expeditions to the loch employed sonar, which identified moving objects in the water which other researchers said showed an object around 20-30 feet long. Video from another visit showed a V-shaped wake on the water on a calm day, along with a possible strange carcass on the loch floor.
 
In 2008, he claimed that the monster may now be extinct, as suggested by the lack of new sonar readings and a decline in eyewitness reports, speculating that the animal may not have been able to adapt to a change in temperature due to global warming. He undertook another expedition using sonar and underwater camera in an unsuccessful attempt to find a carcass.
 
Outwith his work on the Loch Ness monster, Mr Rines taught at the Massachusetts Institute of Technology and at Harvard, specialising in patent law and invention, and also wrote music for a number of Broadway musicals.