The Justice Department has confirmed it’s opened a criminal and civil investigation into the BP oil spill in the Gulf Coast, now believed to be the worst environmental disaster in US history. Eric Holder made the announcement following a meeting with federal and state prosecutors in New Orleans.

Attorney General Eric Holder: “Yes, we have begun both a criminal as well as a civil investigation, as is our obligation under the law. Our environmental laws are very clear, and we have a responsibility to enforce them, and we will do so. I don’t want to describe exactly who is under investigation. At this point the investigation is and has been ongoing for some time, but I wouldn’t want to specify at this point who the targets or the subjects are of that investigation.”

News of the investigation helped plunge BP’s stock value 15 percent on Tuesday. BP also announced it’s effectively abandoned any hope of plugging the breached well and instead will try to siphon off the leak until relief wells are completed in August. Earlier in the day, President Obama promised a thorough probe after meeting with the chairs of the bipartisan commission investigating the oil spill.

President Obama: “Untold damage is being done to the environment, damage that could last for decades. We owe all those who have been harmed, as well as future generations, a full and vigorous accounting of the events that led what has now become the worst oil spill in US history. Only then can we be assured that deepwater drilling can take place safely.”