Suspects in the serial bombings on July 11 of the city's commuter train network have confessed they went to Pakistan for training in arms and explosives, the police in India said today, and at least one has testified that he received instructions from an operative of a banned terrorist organization operating across the border. The statements by senior police officials represent the first glint of evidence of complicity by the Pakistani-based militant group, Lashkar-e-Taiba, that Indian officials have blamed repeatedly for terror attacks on Indian soil. The chief of the Mumbai police antiterrorist squad, K. P. Raghuvanshi, said today that six of the eight suspects confessed to having gone for military training in Pakistan. The police have not described precisely how the 8 men are linked to each other or, more importantly, to the blasts, which killed 183 people during the evening rush hour.