"We wrote a letter addressed to Preity Zinta and handed it over to her lawyer Hitesh Jain asking the actress to be present before us within three days or latest by this weekend," an IPS officer privy to the investigation said.
"We have learnt that Preity Zinta is not in India and hence, we gave the letter to her lawyer," he said.
The officer said Zinta's detailed statement was required "at this juncture" as several queries needed to be answered before proceeding further.
He said the investigators wanted to ask the actress about the exact place where the alleged incident took place and who were around.
At one point of time, the actress claimed, "I left for my seat, but he (Ness) came up to me at my seat and started screaming and abusing me in front of everyone."
"We want to know where she was sitting and who were these 'everyone' she was referring to," the officer said.
The police apparently want to record Preity Zinta's detailed statement as the CCTV footages obtained by them do not contain the alleged spat between the two.
"We will seek some more CCTV footage in the coming days as whatever footage we have got do not show any spat between the two," he said.
Investigators have indicated that Ness would be called for questioning only after recording Zinta's statement.
The 39-year-old actress had filed a police complaint last Thursday night alleging that she was molested by Wadia (44) inside Wankhede stadium on May 30 when an IPL match was played between Kings XI Punjab and Chennai Super Kings.
Zinta and Wadia had broken off their five-year-long relationship a couple of years ago but continued to share business interest.
Several players of IPL team Kings XI Punjab, of which Zinta is a co-owner with Wadia, its support staff, and officials of Wankhede Stadium were claimed to have been present when the alleged incident took place.
Based on Zinta's written complaint, Marine Drive police registered an FIR against Wadia under IPC sections 354 (assault or criminal force to woman with intent to outrage her modesty), 504 (intentional insult with intent to provoke breach of peace), 506 (criminal intimidation) and 509 (word, gesture or act intended to insult the modesty of a woman).
Meanwhile, Zinta's lawyer Jain has said the actress had accused Wadia of outraging her modesty by abusing her in public and making her feel ashamed.
"There was, however, no allegation of 'sexual molestation' as claimed in a section of the media," he said.