New Delhi, Feb 16: The Supreme Court was Thursday told that the 2008 Mumbai terror attack convict and Pakistani terrorist Ajmal Kasab and his nine associates had planned to return to Karachi by the sea route after the carnage.

Senior counsel Gopal subramanium, appearing for the Maharashtra government, told the apex court bench of Justice Aftab Alam and Justice C.K. Prasad that the "GPS (global positioning system) was an important device for 26/11 terrorists to reach Mumbai and there was record of their return journey from Mumbai to Karachi" also.

The court was hearing Kasab's plea challenging the upholding of his conviction and award of death penalty.

Kasab was convicted and awarded death sentence by a Mumbai trial court May 6, 2010. Besides other charges, he was convicted for waging war against India. The Bombay High Court upheld the verdict Feb 21, 2011.