The problem as I see it is why CO thought it safe to continue from EWR to DEL with this guy on board...how did anyone know what his intentions were? was it as 'simple' as a murder and thats it? How in the world did anyone know that it ended there? and that his bags were well screened? that he was not now suicidal and wanted to take everyone with him or a few sitting next to him? Could it be handled on board (w a marshall?) Why not land asap?
As pilots here, if you were in this position not knowing anything except what 'the authorities' knew at that time ie that this guy murdered two people, what would you do? How much pressure would company interests play. My guess is that going back or diverting would cost the airline lots of dollars. Was that a factor and how big?
I will say without knowing the full details...I do hope the pilot made the final call, his responsibility, but I think company interests may have played too big a role here. Thoughts?