A shark believed to behind a series of attacks off Sharm el Sheikh, Egypt, may have a damaged sensory system leaving it unable to distinguish between a human and a vulnerable fish, according to a leading marine biologist.

Aviv Levy, curator of the Red Sea observatory in Eilat, Israel, told The Times: “Most sharks take one bite and that’s it, Normally after the first bite they run away. This guy went on and bit somebody else. I’ve never heard of that.

“It is several years’ worth of shark attacks in a few days. I’d say it’s one shark. Maybe something in its sensory system changed and it has problems [distinguishing] between humans and injured fish.”

The attack on a 70-year-old German tourist at the weekend was Egypt’s first shark fatality in five years, and took place near just Marsa Alam, a remote diving area a long way from Sharm el-Sheikh, where such attacks are almost unheard of.

It is thought that the shark – believed to be an oceanic whitetip – was forced towards the shore due to overfishing in its deep sea feeding grounds. It also could have been attracted by meat thrown overboard by captains of trading ships following the Muslim Eid festival last month.

Oceanic whitetips are considered far less aggressive than great whites, but they are known for preying on humans when they are already vulnerable, in cases of shipwreck, or planes crashing into the sea.

Holiday firms have cancelled diving and other water sports around the resort of Sharm.

Egyptian authorities are desperate to identify and kill the shark to reassure tourists, who are vital to the country’s economy.

Two sharks, a whitetip and a mako, were caught and killed last week, but conservation experts warning that they did not resemble photographs taken of the predator following the second attack.

Egyptian authorities have now enlisted three international experts to fly to the resort to investigate.

Lifeguards have been ordered to stop people swimming in the area, but scuba diving in some areas resumes today, and the country’s tourism minister insisted that divers were “100 per cent secure”.

Tourism minister Zuhair Garana said: “Diving is being allowed. We are advised that sharks will not attack divers. One of the main reasons for people coming here is to dive and to see sharks.

“I cannot say that deep waters are completely secure but shallow waters are 100 per cent secure.”