Suspended Mumbai Police officer Sachin Vaze and former policeman Vinayak Shinde were present at the meeting where the murder of Thane-based businessman Mansukh Hiran was planned, the NIA told the court on Tuesday and added Waze had used a mobile phone to contact "conspirator".
The agency also said that it was close to unravelling the conspiracy and the motive behind the crime.
The special court judge P R Sitre has extended till April 7 the NIA custody of Shinde and another accused Naresh Gor, a cricket bookie, in the murder case.
Hiran, a Thane resident, had been in possession of an SUV which was later found with explosives near the residence of industrialist Mukesh Ambani in south Mumbai on February 25.
The body of Hiran was found in the Mumbra creek in Thane on March 5.
The Maharashtra Anti-Terrorism Squad had arrested suspended constable Shinde and Gor in this connection earlier this month.
The National Investigation Agency (NIA) took the duo into its custody last week. They were presented before the special NIA court on the expiry of their remand on Tuesday.
The NIA told the court that its probe revealed that Vaze and Shinde were present at the meeting where the murder of Hiran was planned.
The agency said it needs to question the accused duo regarding the recovery of seven SIM cards, some mobile phones and a CPU during the probe.
These SIM cards and mobile phones were recovered from Shinde, the court was told.
Special public prosecutor for NIA Sunil Gonsalves told the court that the probe team found a piece of paper during the probe listing 14 mobile phone numbers, of which five numbers were given to Waze.
One of the mobile phones was also given to Vaze, which he used for contacting "conspirator" to kill Hiran, the agency told the court.
The NIA further said the agency is closer to unravel the conspiracy and the motive behind killing Hiran.
Shinde's lawyer Gautam Jain submitted that no role in the crimehas been attributed to the accused other than the delivery of the SIM cards.
He said Shinde's further remand is not required as he has been in the custody of the probe agencies (first the ATS and then the NIA) for almost nine days.
Gor's lawyer Aftab Diamondwale told the court that his client's role was restricted to providing the SIM cards and that he is not connected to the (murder) case.
Diamondwale told the court that Gor has been falsely implicated in the case.
The Hiran murder case was initially probed by the Maharashtra ATS, but it was later taken over by the NIA.
The NIA is also probing the case of the bomb scare outside Ambani's residence and arrested Vaze.
The central probe agency earlier told the court that both the cases were connected.
Waze is in the NIA's custody till April 3.