An area in Uttar Pradesh [Images] has become a crucial lead in the investigation into Saturday's serial bomb blasts in New Delhi [Images] as police questioned scores of people in an effort to crack the case.

Investigation have revealed that several anonymous calls had been made to the particular area in the state before and after the blasts and these are being verified, police sources said in New Delhi on Monday.

•  The message from the blasts

The suspected calls had been made from both mobile and landline phones to particular numbers, they said.

Police were also examining a possible link of the Delhi blasts with the module of Lashker-e-Tayiba that attacked the Ayodhya makeshift temple in July, as some similarities had been found, the sources said.

Racing against time to find a breakthrough in the case, police questioned scores of people, including the passengers of the bus in which a bomb was detected in time and thrown out by the alert crew to avert a major tragedy.

•  Eerie silence in Delhi hospitals

Investigations are immensely dependent on descriptions given by the passengers of the bus.

A man had given the bag to one Umer before alighting from the bus near Govindpuri.

Umer had subsequently raised an alarm but was yet to be traced by police.

"We have a rough description of the person but we want to be absolutely sure before releasing any sketch," Joint Commissioner of Police (Special Cell) Karnal Singh told reporters in New Delhi.

•  Delhi blasts: Death toll rises to 62

Police also displayed two bags similar to the ones believed to have been used by the terrorists and appealed to the public to inform as to who had sold these to suspicious persons.

"The shopkeepers who sold such bags may give some valuable information," the joint commissioner of police said.

With very little evidence recovered from the sites of the blasts, police feel that descriptions of the suspected terrorists and forensic reports, which may take a few days to come in, would be of immense help.

•  Delhi Police get string of hoax calls

"We have recovered only bits and pieces from the spots. We are trying to piece them together," Singh said.

Throughout the day, Home Ministry and intelligence officials held a series of discussions to review the situation.

Singh said, though it was difficult to pinpoint which organisation may have carried out the blasts, it was almost certain that only one was involved.

On Sunday, the Islamic Inquilab Mehaz, an outfit closely linked to Pakistan-based Lashkar-e-Toiba claimed that it had carried out the attacks.

•  Police search for terrorists

Police teams had also been sent to several places, including Punjab, from where the Babbar Khalsa, which carried out the cinema hall twin blasts in May, operated.

Investigations had also revealed that no cylinders had exploded in Sarojini Nagar as speculated earlier. Rather, the extensive damage had been caused as large containers of kerosene and cooking oils ignited.

Singh said 10 bodies were yet to be identified or were disputed and DNA tests would be carried out on these.

Meanwhile, Police Commissioner K K Paul, in a Diwali eve message to policemen, said, "each and every element of terror needs to be identified and their attempts at disturbing peace and communal harmony thwarted."

•  Inquilab group linked to LeT

Intelligence sources said there was a possibility of few of the LeT's terrorist modules, which had a close-knit network of a handful of militants, had been activated to carry out side-attacks.

The agencies were also looking at the new angle with regard to the use of electronic-timer devices, which had been used in terrorist attacks in the country for the first time.

The sources said the security agencies were flushed with a lot of data, which were being surfed to provide any possible clues leading to the serial blasts of Saturday.

•  'Outfit behind blasts is ISI-backed'

The possibility of the conspiracy for the attack being worked out in a foreign country was also being studied, the sources said, adding that there were definite leads to prove that the plan of July five attack at the disputed Ayodhya complex was worked out in the Lashkar-e-Toiba camps along the Bangladesh-Myanmar border.

There are about five LeT camps in the Arakan Hills. The conspiracy was hatched in one of them and carried out through Nepal, the sources said.

Complete Coverage: Terror strikes Delhi