Congress candidate N. Munirathna Naidu from Bengaluru's Rajarajeshwari Nagar Assembly segment has been booked in connection with the recovery of about 10,000 voter ID cards from a flat, along with over a lakh counterfoils of acknowledgement slips, police said on Thursday.

"He (Naidu) was named as an accused in the FIR registered on Thursday on the basis of a complaint over the recovery of the voter ID cards from the apartment," Additional Commissioner of Police (West) Bijay Kumar Singh told IANS here.

Naidu is also an outgoing legislator of the ruling party from the same constituency he is contesting in the May 12 Karnataka Assembly polls.

The Congress candidate was booked under various sections of the Indian Penal Code (IPC) and the Representation of People Act, 1951, for bribery and undue influence in an election.

The police had arrested two persons on Wednesday -- one for committing the electoral offence of keeping a large number of voter cards there and another for breaking into the apartment where the voter cards and counterfoils were kept, without informing the Election Commission (EC) authorities, Singh told IANS earlier.

State Chief Electoral Officer (CEO) Sanjiv Kumar told reporters here on Wednesday that a total of 9,896 voter cards and over a lakh counterfoils resembling acknowledgement slips were seized from a flat in the assembly constituency.

Preliminary investigation showed that the voter cards were genuine, but the counterfoils were yet to be verified, Kumar had said.

"All the materials have been seized and investigation is going on under the supervision of the EC. The materials indicate a planned work over a period of time to survey and locate the vulnerable electors and induce them through middlemen," he said.

The ruling Congress blamed the opposition Bharatiya Janata Party (BJP) after the incident, calling it a conspiracy hatched by the party leaders in the apartment that allegedly belonged to a former BJP Corporator Manjula Nanjamari.

On the other hand, the BJP urged the EC to countermand the election in the constituency, terming the incident an attempt by the ruling Congress to rig the election.

The Assembly election across 223 constituencies of the state will be held on May 12. Votes will be counted on May 15.

Of the 225-member lower House, election in the Jayanagar seat in south Bangalore has been countermanded owing to the death of BJP candidate B.N. Vijaya Kumar on May 4, while one member is nominated.