Shiv Menon, who lives abroad, is Pushkar’s son from her previous husband.
“We have asked Pushkar’s son to join in the probe,” said Delhi Police Commissioner BS Bassi.
A team of Delhi Police probing the murder has questioned at least 15 people in connection with the case. Among them are her husband and Congress MP Shashi Tharoor, his official staff members and close friends.
On Wednesday, they questioned another friend of Pushkar, former Samajwadi Party leader Amar Singh.
Amar Singh recently told the media that Pushkar was depressed over the IPL fiasco which led to the removal of the Kerala franchise in which she had considerable sweat equity.
He added that she had broken down and wanted to reveal information about the IPL controversy to him.
Officials said that Menon would likely come to Delhi by this weekend. The officials will try to find out if he was told anything by Pushkar before her death.
Pushkar was found dead in a luxury hotel room in New Delhi on January 17, 2014. A murder case was registered by police against unknown people on January 1 this year.