The men were caught by CBI chief Alok Verma's security personnel and taken inside

Highlights Four men found sitting in car outside CBI chief's home

Alok Verma's security guards caught the men

The men were handed over to the police and a case was filed

Four officials of the Intelligence Bureau were caught at exiled CBI chief Alok Verma's Delhi home this morning and accused of snooping from parked cars, in continuing drama involving the country's main investigating agency.

In visuals looped on TV channels, the spies stumbled and fought as they were dragged by their shirts by security personnel at Mr Verma's 2 Janpath home (named CBI House since Wednesday night, according to officials). The incident took place around 7:45 am.

That the spies were caught on camera and also arrested, gives a fascinating glimpse into what many would describe as turmoil and disconnect between various agencies. After being handed over to the police, they gave their names -- Dheeraj Kumar, Ajay Kumar, Prashant Kumar and Vineet Kumar Gupta.

In a sharp response, the Intelligence Bureau said there was no snooping and the men had stopped to check on an "unusual collection of people" at the house. Officials said the bureau is responsible for collecting intelligence on situations that may affect public order and internal security.

"(Our) units are routinely deployed on a regular basis in sensitive areas. At times, this is done in association with local law enforcement agencies and at other times, a surprise element is also built in," said officials to NDTV on the inexplicable footage.

CBI chief Alok Verma was abruptly sent on forced leave yesterday and replaced by an interim chief

Sources said there is a possibility that the men, whose IDs and phones were taken away, were tasked with monitoring Mr Verma's visitors. It would not be unusual.

"This is unlike surveillance, which is done covertly, without any visible appurtenances," the Intelligence Bureau insisted. "One such unit, in early hours of today, halted on Janpath, where there was an unusual collection of people. This was with a view to check the reason why people had collected at the location. This is a high security zone where several protectees reside. Unfortunately, their presence was projected otherwise," said the bureau's statement.

"Would they carry I-cards if they were in covert intelligence?" a top officer said.

Rakesh Asthana, who has been charged in a case filed by the CBI, has also been sent on leave.

When the police -- Mr Verma was Delhi Police commissioner before he became CBI boss -- were called, the men were detained.

On record, the police denied any arrest. "We have not detained anyone," senior officer Madhur Verma told the Press Trust of India.

Despite the Intelligence Bureau's clarification, the strange incident fuelled speculation of surveillance on Mr Verma, who was abruptly sent on forced leave yesterday and replaced by an interim chief, days after he launched an investigation against his deputy Rakesh Asthana, accusing him of corruption.

Mr Asthana, who has been charged in a case filed by the CBI, has also been sent on leave but is seen to have fared better in the CBI bloodbath than his boss. Officers on Mr Verma's team, who were investigating half a dozen charges against Mr Asthana including bribe-taking, were moved out in a mass transfer ordered by M Nageswar Rao, who took over the CBI director's responsibilities around 2 am on Tuesday night.

An Intelligence Bureau operative is overpowered by CBI chief Alok Verma's security guards

The overnight activity took place reportedly under National Security Adviser Ajit Doval's supervision; he set the process in motion by asking for an order divesting Mr Verma of his powers and replacing him with an interim chief. The CBI building was cordoned off around 10.30 pm. The order came out around 1 am and soon Mr Rao drove into the headquarters, escorted by police cars.

The feud between the CBI's top two officers escalated after the agency filed a case against Mr Asthana who has been described as "Prime Minister Narendra Modi's blue-eyed boy" by Congress President Rahul Gandhi.