Washington, Feb 9 (IANS) A Pentagon watchdog has found that ineffective implementation of social distancing and the premature release of sailors from quarantine were the primary causes of the massive Covid-19 outbreak onboard the USS Theodore Roosevelt aircraft carrier last year.The Navy had appropriate plans in place to counter a potential outbreak of an infectious disease, but the leadership of the aircraft carrier did not fully implement the required measures, the Defence Department's Inspector General said in a report released on Monday.The vessel's leadership also "allowed social gathering areas to remain open" and continued to conduct urine tests for illegal drugs despite the threat posed by Covid-19 and procedures outlined by the Navy, the report said.The Roosevelt had just completed a port call in Da Nang, Vietnam, when it reported its first Covid-19 case on March 24, 2020. At least 1,271 sailors of the 4,800-member crew aboard the aircraft carrier were infected with the virus last spring. One crew member died.Brett Crozier, the vessel's commander, wrote a letter to his superiors outlining the dire situation and pleading for help to evacuate the ship.Crozier was relieved of his command after his letter leaked to the media. The then-Acting Navy Secretary Thomas Modly said at the time that Crozier was removed because he sent the "non-secure unclassified email" to a "broad array of people". --IANS ksk/