A commuter clutches a handgrip on a local train in Mumbai on Thursday. (AFP)

July 13: The Mumbai train blasts cast a shadow on the India-Pakistan peace process with Nepal police making the first arrests in the case by picking up four Pakistanis in Kathmandu.

Police suspect Ghulam Hussein Cheema ? held with Atta Moinuddin Siddiqui from Everest Hotel at New Baneshwor ? is a former Pakistan embassy staffer who had earlier been arrested with 16 kg of RDX on April 11, 2001. Asif Ali and Sajid Ali were picked up from Hotel Jagat in Thamel last evening.

Delhi didn’t officially blame Islamabad for Tuesday’s carnage but sources said the foreign secretary-level talks scheduled in Delhi on July 20-21 could now be delayed.

National Security Adviser M.K. Narayanan briefed senior cabinet ministers on the probe, mentioning phone calls made to Karachi and Dubai just before and after the blasts.

Foreign office sources hinted that Pakistan would not be accused before definite proof comes along, but till then the composite dialogue could be suspended.

Late at night, President Pervez Musharraf said Pakistan was willing to help with the investigations.

In Mumbai, the police made little headway, detaining suspects by the score only to release most of them. But officers claimed credit for the Kathmandu arrests

“We traced calls made from Mumbai to Nepal after the blasts and also on Wednesday. We alerted the home ministry which got in touch with the Indian mission in Kathmandu,” an officer said.

Late tonight, the police began raids in Thane’s Padga area, 60 km from Mumbai, where four Simi activists had been arrested in April 2003 in connection with the Mulund station blasts that killed 12. The police believe Simi activist Imtiyaz Batkal, involved in that attack, had a role in Tuesday’s blasts.

Padga is near a village where the underground Gujarat Revenge Group, formed to avenge the post-Godhra riots, is believed to have operatives.

A hunt is on for four former Simi activists who disappeared from Solapur a week before the blasts, and reports have been sought on their colleagues in Malegaon, Aurangabad, Nashik and Nanded. Two madarsas in Aurangabad, run by former Simi activists, are under the scanner.

Agency reports quoted police sources as saying the mastermind of the Delhi pre-Diwali blasts, Lashkar-e-Toiba operative Rahil, may have planned Tuesday’s carnage.

False hopes of a breakthrough came when Hyderabad police detained Mohammed Abu Taha, also known as Abdullah, as he arrived on a train from Mumbai yesterday morning. He was carrying a diary full of addresses and Pakistani phone numbers.

He was let off this evening. “He seems to have no links with the blasts,” Andhra police chief Swaranjit Sen said.