Central Crime Branch of the city police on Friday arrested a relative of former Chief Minister M. Karunanidhi on charges of usurping 16 grounds of land on Kumarappa Street, Kasi Garden in Nungambakkam and threatening the trustees of the land.

The plot is worth over Rs. 100 crore.

CCB sources said the suspect Uma Maheshwari (53) is a resident of St. Mary’s Road in Alwarpet.

In 2006, she along with her accomplices threatened complainant Ethis Gupta, the treasurer of the trust, and demanded that the trust register 14 grounds of the land, owned and maintained by it since 1915, in her name.

Fearing for their lives, Gupta and the other trustees agreed for the sale but were forced to write off 16 grounds finally.

The suspect paid only Rs. 1.7 crore out of the promised Rs. 8 crore which was already way lesser than the market price.

When the complainants repeatedly asked for the rest of the amount, Uma threatened to grab the remaining 4.5 grounds owned by the trust as well.

In June, Uma reportedly sold the land to a builder following which Gupta approached the Office of the Commissioner of Police with a complaint on Tuesday.

A CCB team investigated the issue and arrested Uma Maheshwari on Saturday, said sources.

She was remanded to custody and sent to Puzhal prison, sources added.