Austrian police were yesterday investigating the deaths of three Irish and one English tourist who were killed while white-water rafting on the Salzach River on Monday.
Their raft, containing nine people, broke its moorings, swept over a fast-flowing weir, dropped into a whirlpool and capsized 50 miles south of Salzburg.
Police said the criminal investigation would consider grounds for charges of negligent manslaughter.
The three Irish people who died were Mr Alan Daly (35), Beechwood, Ballivor, Co Meath; Mr John Thomas Geough (28), who has a London address and was working in a bank; Ms Emma Duke (28), Claremont Pines, Carrickmines, Dublin.
Mr Daly's wife, Clodagh, was injured in the accident and is in hospital in Schwarzach.
A spokeswoman for the Department of Foreign Affairs said Irish Embassy officials in Vienna were liaising with the Austrian authorities. The next of kin and relatives of the dead and injured had travelled to the scene.
Regarding the police investigation, Zell am See police Insp Johann Lengaur said: "It is not possible to say whether this will result in charges, but statements have been taken and evidence seized, including the broken rope that led to the raft plunging into forbidden rapids and the boat itself.
"We are looking into the case on behalf of the public prosecutor's office in Salzburg on suspicion of negligent manslaughter. The investigation will take at least a month and a report will then be passed on to Salzburg prosecutors."
The director of the Department of Lake and River Navigation in Salzburg, Mr Peter Maier, said all boats and equipment at the Taxenbach Rafting Center, which provided the instructors and equipment for the ill-fated expedition, would be investigated.
Mr Maier said the rope used to stop the boat was a safety rope intended only to pull passengers out of the water, and was not strong enough to pull the boat to land. He said the rope probably tore when it was thrown over the safety rope spanning the Salzach river, in a last ditch effort to stop the raft going down the rapids and bring the rafters to safety.
Mr Trevor Hamer, the rafting centre's owner, said conditions were good when the tragedy happened.
"The river was at a normal level for the time of year, although it had been in flood last week," he said.
"The sun was shining and conditions were very favourable for rafting."
The boats, which travelled in pairs, were below their capacity of 11 tourists and there was a guide on each. The raft that went over the weir contained nine people, the other held eight.
The first craft had docked normally before the weir when something happened to the second boat and it went over the edge, Mr Hamer said.
"When things started to go wrong, the staff followed all safety procedures to the letter," he said.
"These, and our safety equipment, exceed what is required by the Austrian authorities."
Part of the rescue attempt involved pushing the already docked boat, which was then empty, over the weir to give those in the water something to cling on to, he added.
Mr Hamer said: "We are still authorised to continue rafting on the river, but all trips have been suspended until we discover what went wrong."
At a press conference yesterday the district governor of Pinzgau, Ms Rosmarie Drexler, asked local rafting businesses to "voluntarily stop all planned trips for the moment". She said only licensed businesses were allowed to raft on the Salzach, and that Mr Trevor Hamer and the boat leader were both licensed.