August was a month of hectic activity for the investigation agencies in India.

Late on the evening of August 18, former Union Finance Minister P Chidambaram was arrested after officers of the Central Bureau of Investigation scaled the walls of his home in New Delhi. The senior Congress leader had played hide and seek with the agency the day before and then dramatically addressed a press conference at the party headquarters before he was taken into custody.

The nine-year-old INX Media case in which he is alleged to have been involved relates to allegations of money laundering. The CBI chose to detain Chidambaram before the Supreme Court could hear his pre-arrest bail application.

Even as a parallel move by the Enforcement Directorate to arrest Chidabaram was stayed temporarily by the apex court, ED investigators last week took Congress leader DK Shivakumar to New Delhi to question him for two days in a corruption case. The former Karnataka minister is a key fund raiser for the Congress in the southern state.

On August 29, the Enforcement Directorarte moved to attach 14 industrial plots in Haryana worth Rs 30 crore in a case that involves former Chief Minister Bhupendra Singh Hooda. The investigation, which comes just months before the state is to face Assembly elections, is trying to establish whether the plots were allotted illegally.

Meanwhile, in the Narada cash-for-favours case in West Bengal, the CBI has upped the ante, asking the Lok Sabha Speaker for permission to prosecute four top Trinamool Congress MPs. At the same time, there has been little movement in the Sarada chit fund scam that involves former Trinamool Congress leader Mukul Roy, who is now a member of the ruling Bharatiya Janata Party.

Both the Congress and the Trinamool Congress have alleged that the BJP is carrying out a political vendetta. After all, as some in the media have noted, it was during Chidambaram’s tenure as Union home minister in 2010 that current Union Home Minister Amit Shah was arrested in Gujarat for his alleged involvement in an extra-judicial execution.

While the CBI and the Enforcement Directorate have accelerated several cases against leaders of the Opposition, the lack of action in cases involving BJP leaders has reinforced the impression that the agencies are functioning in a partisan fashion. For example, the corruption cases involving Karnataka Chief Minister BS Yeddyurappa are gathering dust. The CBI has not yet filed an appeal against his acquittal by the trial court in 2016.

There is no question that the government is duty-bound to take decisive action against corruption. But the perception that it is acting selectively will discredit its campaign against graft and further undermine public confidence in the independence of the investigative agencies.