max so cnn has learned that congressional democrats are investigating whether top us oil companies considered a conspired rather with opec to push up gas prices isis they've sent a letter to exxon mobil, chevron, hessd three other fossil fuel companies demanding documents, including their communications with opec. our earlier this month, federal regulators accused texas oil icon scott sheffield of allegedly conspiring with opec to raise prices, raising concern over whether this has been common practice among other companies. >> cnn's matt egan helped break the story. >> any joins us now with the latest on this, what do you know? map. >> but boris and jessica, a big oil is facing new scrutiny from congress over a topic that we know americans care deeply about. gas prices. now, new jersey democrat frank pallone, he's launched investigation into seven of the biggest players in oil, exon, chevron, bp, shell, devin energy, occidental, and hess and the big question is, he's asking whether or not these oil companies colluded with either each other or with opec to jack up the price of oil and gasoline by agreeing to keep supply low. let me read you from this letter from pallone to the oil companies. he wro