A team of federal investigators known as the "BP squad" is assembling...to conduct a wide-ranging criminal probe that will focus on at least three companies and examine whether their cozy relations with federal regulators contributed to the oil disaster...Scott Dean, a spokesman for…BP, said the company "will cooperate with any inquiry the Justice Department undertakes, just as we are doing in response to other inquiries that are ongoing."…Although lawyers familiar with the case expect that environmental-related charges -- which have a low burden of proof -- will be filed, some doubted that investigators can prove more serious violations such as lying or falsifying test results…The official said that no decisions on criminal charges are imminent [also refers to Transocean, Halliburton]