an attorney for at least one of the officers , michael davey , said thursday that gray was not strapped in during transport .
the 25-year-old was cuffed at the wrists and shackled at the ankles - he was found to have a fatal spine injury , but the cause remains unknown .
` nickel rides ' have caused spinal injuries in the past . another baltimore man , dondi johnson , was killed by such a ride in 2005 .
department rules were updated nine days before gray 's arrest stating that all detainees shall be strapped in by seat belts or other device .