Industrialist Sunjay Kapur, embroiled in a legal battle with estranged wife and actress Karisma Kapoor, has complained to the Delhi police that he has received an extortion threat.

Kapur said he recieved an e-mail on Friday evening demanding Rs 50 crore.

"We have registered a case and are carrying out investigations," Joint Commissioner of Police (Special Cell) Karnal Singh said on Saturday.

Also read: Karisma's husband files case against her

It was not clear whether the demand was connected with the tussle between Sunjay and Bollywood actor Karisma over the custody of their five-month-old daughter Samaira.
    
Sunjay had alleged that Karisma had got a passport issued to their minor daughter without his consent by flouting all laws and that she was planning to leave for the US along with Samaira without taking him into confidence.

Also read: Sanjay deserted me: Karisma tells HC

The Delhi high court had passed an the interim order restraining Karisma from taking the child abroad.