SK Warship sank by USS Columbia ?

Some independent minded commentators are pointing the finger at the
US nuclear submarine the USS Columbia which is said to have disappeared.They argue that during the US-SK Foal Eagle exercises there was a "friendly fire" incident involving the USS Columbia and the Cheonan with the result both sank.

The whole incident is being used to achieve several ends
a)SK to whip up anti DPRK hysteria
b)US to smear and blacken the DPRK's name
c)US and SK to apply more so called sanctions against DPRK
d)SK to repress pro reunification forces and fake spy cases
e) US to retain Okinawa base in Japan.