.Madan Mitra, one of the senior leaders of the Trinamool Congress, who traces his political roots to the Congress, has spent the first couple of nights in police custody, just a week after his 60th birthday. The Central Bureau of Investigation (CBI) remanded him to custody on Saturday and almost no one, including his party colleagues, is expecting Mr. Mitra to get bail any time soon.

Mr. Mitra, born into a politically connected, landowning and business family of South Kolkata, started his political career in the ’70s as an aide of former Union Minister Priyaranjan Dasmunshi. He stayed with Mr. Dasmunshi over the next few decades and became an important student leader in South Kolkata. Within the Congress, Mr. Mitra and Mamata Banerjee were in rival camps. “They both are of the same age and joined the student’s wing of the Congress early in their career, and thus challenged each other on several occasions,” recalled a senior Congress leader.

Before shifting to the Trinamool Congress in the ’90s, Mr. Mitra had emerged as a Congress strongman, challenging the Left Front in South Kolkata. He launched a taxi driver’s union and wrested control of the union at the prestigious SSKM government hospital. He emerged as one of those leaders who created his own brand beyond the party, and was often described as a person who “helps” every one, irrespective of political affiliation. “He controlled many local boys’ clubs and could handle any critical situation using his boys [cadre] and money power,” said an industrialist, who managed to evict slum dwellers with the help of “Madanda” as Mr Mitra was known, in the ’90s.

An accessible and affable politician, Mr. Mitra made friends across political parties, business houses, NGOs and the film industry.

However, he has been at the centre of several controversies since the Trinamool Congress came to power in 2011. Many who attended his son’s marriage were astounded at the extravagance. The Bengali film industry, sports and business community were fully represented at the lavish event.

Opposition parties raised questions about Mr. Mitra’s role in the death of a woman lawyer and alleged that the case was never investigated properly. Mr. Mitra publicly heaped praise on Saradha Group chief Sudipta Sen, describing him as an outstanding achiever.

In recent months, Mr. Mitra, who had always shared a cordial relationship with the media, has been annoyed at his “trial by the media” as the Saradha scam unfolded and his connections with the tainted entrepreneur became evident.

Ms. Banerjee hardly questioned her lieutenant; Mr. Mitra managed party funds and cadre and organised vehicles and logistics during elections. Though the Chief Minister has started distancing herself from Mr. Mitra, she strongly defended him after his arrest on Friday, describing it as the “politics of vendetta.”

With the arrest of a key lieutenant, Ms. Banerjee is expected to face multiple problems. She will have to rally round his cadre and prevent an exodus from the party. The arrest of key aides — Kunal Ghosh, Srinjoy Bose and now Mr. Mitra — has also left her with little room to revive her ties with the BJP.