The Congress-Trinamul mahajot may have collapsed but Calcutta police have forged a grand alliance of graffiti offenders, slapping cases on the warring allies and the rival CPM for defacing the wall of a government building near Alimuddin Street.

Election graffiti of all three parties are splashed across a wall of Calcutta University’s post-graduate boys’ hostel in Waliullah Lane, off Ripon Street, in violation of the model code of conduct that prohibits poll publicity on government buildings.

An officer of Taltala police station said suo motu cases were filed on Friday against the three parties on charges of defiling government property in ward 62.

“It’s illegal to use any government wall for campaigning. We have registered cases under Section 202 of the Calcutta Municipal Corporation Act, 1980, and forwarded these to the State Election Commission,” he added.

The same rule applies to private walls being defaced without the written consent of the owners. Offenders can be jailed for up to six months and/or fined up to Rs 50,000. The quirk in the law is that the police can take penal action against those who defaced the wall rather than those who asked them to do it.

Khalil Ahmed, the district magistrate of South 24-Parganas and the returning officer for the May 30 civic polls, said he was glad the police had acted on their own. “This is a unique instance of three parties being involved in the same violation. We had advised the police to take action wherever they came across any violation,” he told Metro.

A senior police officer in Lalbazar said the onus was now on the returning officer to issue notices to the parties to whitewash the defaced portions of the wall or face action.

If the parties don’t respond, the State Election Commission will get the wall whitewashed and the expenditure will be recovered from those responsible for the defacement. The amount will also be added to the election expenditure of the candidates concerned.

Hostel inmates said they had seen the names, party symbols and slogans of CPM candidate Mohammed Mahfooz Afroz Siddiqui, Trinamul Congress nominee Iqbal Ahmed and Congress contender Asfaque Ahmed being painted on the front wall but didn’t dare protest.

“Those who wrote the graffiti are all goons,” said a student of political science who stays in the hostel, a shout away from the CPM headquarters on Alimuddin Street.

Trinamul Congress candidate Iqbal Ahmed claimed to be unaware of his supporters defacing a wall of the hostel.

“I will ensure that they whitewash the wall by Saturday,” he promised.

His CPM counterpart Mahfooz Afroz Siddiqui said his men might have written on the wall “by mistake”.

“I will ask them to erase the graffiti,” he added.

Congress candidate Asfaque Ahmed was unavailable for comment.