The wreckage of BP's ruptured Gulf of Mexico oil rig will be the focus of a massive probe as authorities begin gathering evidence from what could amount to a crime scene at the bottom of the sea.
The Deepwater Horizon rig's failed blowout preventer and the twisted remnants of the drilling platform may be "exhibit A" in the effort to establish who is responsible for the biggest peacetime oil spill in history, with the companies under investigation in charge of recovering the evidence.
The FBI is conducting a criminal investigation, the US Coast Guard is seeking the cause of the blast, and lawyers are pursuing millions in damages for the families of the 11 workers killed, the dozens injured and the thousands whose livelihoods have been damaged since the rig exploded off Louisiana on April 20.
"The items at the bottom of the sea are a big deal for everybody," said Stephen Herman, a New Orleans lawyer for injured rig workers and others.
BP will surely want a look at the items, particularly if it tries to shift responsibility for the disaster on to other companies such as Transocean which owned the oil platform, Halliburton which supplied the crew that was cementing the well, and Cameron International, maker of the blowout preventer.
BP and Transocean - which could face heavy penalties if found to be at fault - have said they will raise some of the wreckage if it can be done without doing more damage to the oil well.
That would give the two companies responsibility for gathering up the very evidence that could be used against them.
Lawyers will be watching, too, to make sure the companies do not do anything untoward, said Brent Coon, representing one of the thousands of plaintiffs seeking damages.
"I think they would do something in front of their own mother if they could," he said. "But the reality is there are a lot of eyes watching them and a lot of smart scientists who would know if they did anything they weren't supposed to."
The crisis in the Gulf appeared to be drawing to a close this week when BP plugged up the top of the blown-out well with mud and then sealed it with cement.
BP senior vice president Kent Wells said crews planned to resume drilling tomorrow night on a relief well more than two miles below the seafloor that will be used to inject mud and cement just above the source of the oil, sealing off the well from the bottom, too.
The two wells should link between August 13 and 15, Mr Wells said.
In other developments yesterday, BP said it might one day drill again into the same undersea reservoir of oil, which is still believed to hold nearly £2.5 billion worth of crude.
But that prospect is unlikely to sit well with Gulf Coast residents furious at the oil giant.
Investigations of the disaster began immediately after the rig blew up.
The US government alone is conducting about a dozen, including several congressional investigations, criminal and civil probes by the Justice Department, and an examination by an expert panel convened by President Barack Obama.
Officials want to find out not only the cause of the explosion, but also how oil drilling a mile or more below the surface can be made safer.
But a final outcome could be years away, particularly if someone is charged with a crime, said David Uhlmann, former chief of the US Justice Department's environmental crimes team.
"Normally an investigation of a case this complicated would take two to three years. This is not a normal case," he said.
"This is the worst environmental disaster in US history. The timetable will be accelerated dramatically, but it still will not be resolved before 2011."