Kolkata, Dec 4 (IANS): The Mamata Banerjee-led West Bengal administration came in for embarrassment Wednesday, as the possibility emerged that a man arrested on suspicion of conspiring to burn the heritage Writers' Buildings was only trying to banish pests.

Files daubed with kerosene were found in the premises of the 18th century structure that serves as the secretariat of the state government. The smell of kerosene Friday from the fifth floor of G Block of building, currently under renovation, sent police into a tizzy.

The area was cordoned off, and Home Secretary Basudeb Banerjee told the media that "someone or a group was trying to set the Writers' Building on fire".

The secretary also announced a probe into the conspiracy. Police swung into action, and formally arrested Jyotirmoy Nandi late Saturday night. A court remanded the man in police custody till Dec 6.

Nandi was booked under charges that carry a maximum punishment of imprisonment for life.

It has since emerged that Nandi was hired by the office of the Registrar of Publications, the home department, to spray pesticide in the department. He has been doing the job for the last few years.

Bismay Roy, registrar of the home publication department, confirmed that Nandi was appointed in a pest-control capacity, and was just going about his job.

"Nandi is innocent, he had no malice or bad intention. He has been carrying out a routine pest control exercise for which he has been contracted by the department. I even told the police this as they were interrogating him," Roy said, adding that he has known Nandi since 2004.

Nandi's wife Aparna explained that kerosene is routinely used to mix the pesticide in. This fact was corroborated by pest-control expert Sneha Gupta.

"It is a routine practice to mix kerosene or similar fuel to pesticides," said Gupta.

As Nandi, the sole bread earner in his family is under arrest, his whole family faces uncertainty. Activists, meanwhile, have been crying foul over his arrest.

A distraught Chitra, Nandi's mother, said the family lived hand-to-mouth, and now even that precarious livelihood was under threat. She feared the legal trouble could ruin her family.

Rights activist Sujato Bhadro said the arrest was illegal, as Nandi's family was neither informed about the action, nor was an arrest memo given to them. Administrative action was taken in haste, he said.

A senior officer, however, said there was nothing illegal about the arrest, but refused to comment on claims of Nandi's innocence.

"Nandi has been booked under Section 436 (mischief by fire or explosive substances with intent to destroy house etc.) and Section 511 (punishment for attempting to commit offences punishable with imprisonment for life) of IPC," Deputy Commissioner (central) of city police D.P. Singh told IANS.

"Investigation is on and we cannot comment on what others are saying. It is for the court to decide on whether he is guilty or innocent," he added.