U.S. Navy presses inquiry into deaths of two divers NORFOLK, Virginia (Reuters) - A defense attorney at a hearing for two Navy officers on Thursday accused the U.S. government of bringing unwarranted charges of involuntary manslaughter and dereliction of duty in the deaths of two divers during a February 26 training exercise in Maryland. "There were two tragedies," that day, said Navy Lieutenant John Butler, representing Senior Chief Petty Officer James Burger. The first tragedy was the deaths of the divers, he said, adding that the charges brought against Burger and Chief Warrant Officer 3 Mark Smith were equally tragic because the men were merely doing their duty. Petty Officer 1st Class James Reyher of Caldwell, Ohio, and Petty Officer 2nd Class Ryan Harris of Gladstone, Missouri, died in 150 feet of water during a training dive. They were attempting to locate a submerged helicopter at a training and weapons site called the Super Pond near Baltimore. Butler and civilian defense attorney Patrick J. McLain said there was ample evidence of malfunctioning diving equipment, including a type of scuba breathing regulator that defense counsel said the Navy has since abandoned. Prosecution and defense presentations during the two-day Article 32 hearing will determine whether there is sufficient evidence to refer the case against the two non-commissioned officers for trial by court-martial. The case could otherwise be handled administratively or the charges could be dismissed. The presiding Navy captain will make a recommendation up the chain of command, and a decision is expected within weeks. Captain Keaton Harrell, prosecuting the case for the Navy, did not offer a summary argument but suggested Burger and Smith had command authority and should have acted more wisely in overseeing the training exercise. Burger was the master diver at the scene and Smith was the officer in charge of the dive group. Commander Michael Runkle, leader of the unit, was relieved of his post after the incident. He was called as a witness Thursday but declined to testify. Neither defendant offered a statement in their defense. Sixteen witnesses were called during the hearing. Witnesses said the divers were never intended to make their dive in conventional scuba gear. They should have used an underwater breathing apparatus called a Mark 16 that would have allowed them more time to work underwater. Not enough devices were available so the decision was taken to make the dive using scuba gear. Reyher and Harris went in, but they had only an 11-minute supply of air and it was soon clear they were staying underwater too long. Another diver was sent in to aid them, but he also had equipment trouble, according to testimony. Two other divers were dispatched to help the missing divers but they soon resurfaced in the 41-degree water. Reyher and Harris were eventually hauled up by a winch but nearly a half an hour after they went in - long after their air supply had been exhausted. Editing By Nick Carey, Steve Gorman and Bill Trott