BP PLC has begun preparatory work for removing the failed blowout preventer from the Macondo well from the Gulf of Mexico seafloor, a move that will aid investigators in the myriad inquiries into the disaster.

A "fishing expedition" over the weekend inside of the Deepwater Horizon blowout preventer found three sections of pipe that engineers hope to remove before raising the 40-foot stack of safety valves later this week, the federal government's point man in charge of the response effort said today.

"Our desire would be to remove those pipes before we proceed with the blowout preventer removal," retired Coast Guard Adm. Thad Allen told reporters today. The target date for raising the 325-ton device is tentatively set for Thursday, he said.

Once the blowout preventer is lifted to the surface, it will pass immediately into Justice Department custody for forensic examination as a potential crime scene, Allen said.

That inspection will also be crucial to other inquiries and investigations into the April 20 explosion and subsequent spill. BP, a White House-appointed commission, Congress, the federal Chemical Safety Board, the Marine Board, the Coast Guard and the Interior Department's Bureau of Ocean Energy Management, Regulation and Enforcement are all conducting investigations into aspects of the spill.

Their findings could affect BP and its subcontractors and partners' culpability in the disaster, fines, liability for cleanup costs and future offshore operating status.

Coast Guard and Interior investigators this week launched their fourth round of spill hearings.

Federal officials for the first time today heard from a representative of one of BP's two "company men" on board the Deepwater Horizon at the time of the accident. Neither Robert Kaluza nor Donald Vidrine, BP's well site leaders on the rig, has been willing to testify at previous hearings.

But today, Kaluza's attorney, Shaun Clarke, spoke up for the first time.

Clarke asked Neil Cramond, BP's marine authority in the Gulf of Mexico, whether Kaluza, who was temporarily filling in on the Deepwater Horizon at the time of the explosion, would have been familiar enough with procedures on the rig to run it.

Cramond said he did not have enough information to answer the question. He also said he did not know whether procedures are uniform across all BP rigs.

Kaluza was well-site leader at Thunder Horse, another BP offshore facility that is capable of both drilling and production. There, he oversaw a crew of drillers from drilling contractor Pride International. Transocean's Deepwater Horizon was only capable of deepwater drilling.

A Transocean shore-based manager of the Deepwater Horizon rig said he had expressed concerns about Kaluza's experience level.

"I challenged BP on the decision. We didn't know who this individual was," Paul Johnson told the joint investigation board.

Johnson said his concerns centered on Kaluza's experience on rigs like the Deepwater Horizon, but he said BP had assured him Kaluza was competent and experienced.

Kaluza has declined to testify at the hearings, citing his Fifth Amendment right. Kaluza has been named a party of interest in the investigation. Vidrine, the other well-site leader, who is not a party of interest, has said he could not testify because of medical reasons.

In a separate line of questioning, Cramond said the captain of the drilling rig has little say in whether a vessel is acceptable to resume work. At issue are the safety concerns noted in a September 2009 internal audit.

U.S. Coast Guard Capt. Hung Nguyen said during Cramond's questioning, "It seems like the companies are emphasizing the drilling operations."

Cramond agreed. "I believe what you've outlined is an accurate picture."

He added that standard industry practice dictates that the offshore installation manager would coordinate all departments on the rig and make decisions about risk. The captain would primarily deal with flag state and international safety management code, although a captain could challenge others in authority if he thought the system was not meeting safety needs, Cramond said.

White House commission preps for hearing

President Obama's commission tasked with investigating the causes and effects of the disaster continues its inquiry this week, as well, holding a public hearing Wednesday in Washington.

The panel will hear from industry and regulatory officials during the meeting, the panel's second hearing.

Bill Reilly, one of the commission's co-chairmen, said last week that the panel will examine details of how an oil industry self-regulating agency might work to fill a gap in the sector's oversight.

"An [Institute of Nuclear Power Operations]-like facility very strongly backed by a regulatory authority, by the government, could really fill that gap," the former U.S. EPA administrator said.