An East Village inferno sparked by a gas explosion in the basement of a sushi restaurant left two people dead and critically injured several others.  The blast happened less than an hour after the local utility inspectors gave the building a failing grade on a gas pipe installation.  The tragedy, per the Manhattan District Attorney’s Office, was a consequence of a scheme by the landlord, who installed an illegal gas line to keep tenants from moving out of the building.  T.J. Russo Consultants was retained to investigate the origin, cause and responsibility for the incident on behalf of an insurance company with several interests.