NEW ORLEANS — Federal prosecutors brought the first criminal charges Tuesday in the Gulf oil spill, accusing a former BP engineer of deleting more than 300 text messages that indicated the blown-out well was spewing far more crude than the company was telling the public at the time.

Two years and four days after the drilling-rig explosion that set off the worst offshore oil spill in U.S. history, Kurt Mix, 50, of Katy, Texas, was arrested and charged with two counts of obstruction of justice for allegedly destroying evidence.

His attorney, Joan McPhee, issued a statement Tuesday evening describing the charges as misguided and that she is confident Mix will be exonerated.

“The government says he intentionally deleted text messages from his phone, but the content of those messages still resides in thousands of e-mails, text messages and other documents that he saved,” she said. “Indeed, the e-mails that Kurt preserved include the very ones highlighted by the government.”

The U.S. Justice Department made it clear that the investigation is still going on and suggested that more people could be arrested. In a statement, Attorney General Eric Holder said prosecutors “will hold accountable those who violated the law in connection with the largest environmental disaster in U.S. history.”

Federal investigators have been looking into the causes of the blowout and the actions of managers, engineers and rig workers at BP and its subcontractors Halliburton and Transocean in the days and hours before the April 20, 2010, explosion.

But the case against Mix focuses only on the aftermath of the blast, when BP scrambled for weeks to plug the leak. Even then, the charges are not really about the disaster itself, but about an alleged attempt to thwart the investigation into it.