William T. White and his team of researchers described the distinct characteristics of the Roughback Bristle Shark through meticulous examination of its size, coloring, body structure, texture, dental arrangement, egg cases, and genetic makeup, and published their their study in the journal "Fishes." Residing at astonishing depths between 2,200 feet and 3,900 feet, the newfound shark species has, thus far, exclusively inhabited the waters off the western coast of New Zealand's North Island. 

The Norwegian Broadcasting Corporation NRK (nrk.no) first reported the diving incident:

An American citizen has been confirmed dead after a diving accident in the Plura Cave in Rana. Although a defibrillator was used after a short time, his life was not saved.

The following is a first-hand statement given to me by one of the divers involved with the fatal dive. They spoke to me on the evening of 4 April 2023. 

The hypothesis has been questioned in a recent study by Dr. Eric E.G. Clua and Dr. Carl G. Meyer, published in a Special Issue of the journal Behaviour. They point out that not only is it unsupported by the evidence, but it fails to stand up to close scrutiny.