Suraj Pancholi was arrested late Monday, Officer D. Deokar said.
Deokar confirmed Khan, 25, committed suicide at her home in Mumbai last week. A letter she wrote alleges that Pancholi cheated on her, physically abused her and forced her to have an abortion. Police authenticated the letter was from Khan, and Indian media have published it.
Pancholi's parents are Aditya Pancholi and Zarina Wahab. Neither they nor their son has spoken about the allegations.
Khan began her career in the 2007 Hindi film "Nishabd," in which she portrayed a teenager in love with her best friend's father, played by Bollywood superstar Amitabh Bachchan. She had also performed with other top stars, including Aamir Khan and Akshay Kumar.
