Even as investigations continue into the theft of 18 computers from one of the Defence Research and Development Organisation's offices in New Delhi, officials believe there is an organised attempt by foreign powers to conduct  espionage in India.

Also see: Espionage not ruled out in DRDO theft

Predictably, they blame Pakistan and its Inter Services Intelligence.

Records of espionage cases cracked by central intelligence agencies throw up an interesting pattern. A large part of espionage activity against India, if these records are to be trusted, is focused around Delhi and states bordering Pakistan.

But questions have been raised about the credibility of some intelligence inputs on espionage. On several occasions, hand drawn maps and such obscure material have been presented as 'incriminating evidence' against the accused.

Iftikar Geelani, a Delhi journalist was arrested in June 2002 and accused of spying for Pakistan. But the case was ultimately withdrawn after it was proved that documents recovered from his home were available on the Internet.

From the Rediff Archives: Government to withdraw case against Geelani

"There might be some loopholes. But more or less, these arrests happen after long field work and intercepts corroboration," a senior intelligence officer said.

The Intelligence Bureau busted seven espionage cases and arrested three Pakistanis and 10 Indians until July. A case each was detected in Punjab, Delhi, Gujarat, Haryana and West Bengal, while two cases were reported from Uttar Pradesh.

"It isn't an unorganised game where there is no clear strategy. They are focused, they know what they want and are rewarded handsomely," said another intelligence officer.

Those arrested for espionage are usually booked under the Official Secrets Act and various sections of the Indian Penal Code.

In 2002, 35 cases of espionage were unearthed; 79 Indians, eight Pakistanis, one Nepali and one Bangladeshi were arrested.

The highest number of espionage cases, six, were reported from Delhi. "There have been some diplomats involved. But we cannot arrest them because they enjoy diplomatic immunity," the officer said.

Espionage cases have also been reported from the northeast. Madhya Pradesh, Andhra Pradesh and West Bengal throw up a case or two a year.

Surprisingly, only one espionage case has been reported from Jammu and Kashmir since 2000.

"Pakistan has a clear picture of what is happening in Jammu and Kashmir so there is little espionage in the classical sense happening there. Also, one must not forget the fact that we have very little network to track suspects. It is a war out there," the officer explained.

Delhi being the focus of covert operations is not surprising because important government offices are located in the capital. In 2000, eight cases of espionage were detected in Delhi, four in 2001 and six in 2002.

Rajasthan reported two espionage cases in 2000, six in 2001 and four in 2002. "In all border states we have found that the ISI is targeting lower level military personnel, retired servicemen and private contractors working for armed forces to ferret out information," the officer said.

In Punjab, seven cases have been reported from 2000 till now.

In some cases, central intelligence agencies claims are not matched by credible evidence. But draconian laws and slow legal processes ensure that the accused spend years behind the bars.

The central intelligence agencies also have to deal with instances of sabotage which are much higher than espionage cases around the country.

Sabotage is loosely defined as an attack, or an attempt thereof, on a strategic installation. For instance, the December 13, 2001 attack on Parliament would not be defined as sabotage, but an attack on a dam would.

Till August 10 cases of sabotage were detected; 11 Indians were arrested, one Indian and three Pakistanis killed.

Two sabotage cases were reported from Maharashtra and two from Delhi. Cases were also reported from Madhya Pradesh and Andhra Pradesh.

In 2000, there were 25 sabotage cases that led to the arrest of 117 Indians, 22 Pakistanis and two persons of other nationalities. Three Indians and two Pakistanis connected to these cases were killed.

In Delhi, 13 sabotage cases were reported each in 2000 and 2001. In 2002, there were 11 cases; till mid-2003 only two cases had been reported in the national capital.

In 2001, Maharashtra reported 15 sabotage cases; three in 2003. In 2000, the state saw only one case.

"In sabotage cases, financial institutions and such sensitive places are the targets. That is why you find so many cases in Maharashtra," the officer said.

In 2001, nine Pakistanis and four Indians connected with sabotage cases were killed, while in 2002 the numbers were -- eight Pakistanis and one Indian.

"Sabotage cases are clearly different. Most of the time we intercept them [the culprits] while they are on their way to execute an attack," an official involved in cracking several sabotage cases said. "Hence, there is a higher number of encounters in such cases."