NEW ORLEANS (AP) -- Federal authorities have blamed two rig supervisors for the deaths of 11 workers killed when the Deepwater Horizon exploded and spawned BP's (BP 1.50%) massive oil spill in the Gulf of Mexico, even though a string of investigations spread fault among a host of people and companies.

A federal indictment last week charged Robert Kaluza and Donald Vidrine with manslaughter, accusing them of botching a crucial safety test. But a defense attorney claims the two BP well site leaders are scapegoats, given that other government probes have concluded blame for the disaster was shared among several individuals and companies.

Shaun Clarke, one of Kaluza's attorneys, says prosecutors are unfairly targeting two men just trying to do their jobs on the rig.