CNN-IBN

Mumbai, Jul 18: A week after a series of blasts ripped through Mumbai local trains, killing nearly 200 and injuring more than 700 people, Mumbai Police are still piecing together the jigsaw.

From nabbing suspects from Nepal and Tripura to tracing phone calls made immediately after the blasts, police and investigating agencies are looking into all possible lead-ins.

So far, phone calls to Pakistan, Bangladesh and Afghanistan were the only telephonic clues. The list includes twelve such phone calls.

However, a call, purportedly made to Australia, has left the police wondering.

According to sources, three calls were made to Bangladesh, two calls to Karachi, two to Afghanistan and one each to Dubai and Australia.

Police believe these calls are a key to cracking the case. Though it's possible to figure out the source of the phone calls, it's tough to trace its destination.

Hence, police are not sure if the call was meant for someone in Australia or if it was re-routed from Australia for tele-conferencing.