Further investigations are being done to recover the identification documents the terrorists presented when seeking registration.
This was after it emerged the gang had arrived in Kenya last month posing as refugees and later drove to Nairobi through Garissa.
The latest group which formed part of the gang was arrested on September 6 along Thika Road as they drove from Garissa aboard a bus for Nairobi.
The two including a secondary school girl Halima Hassan Charfi of Moi Girls Secondary School in Marsabit and Ashraf Yassin Abdulrahman were later charged with being members of Al-Shabaab.
Yassin pleaded guilty of being in the country illegally. Halima had escaped school in 2010 in Marsabit and joined the terror group after being recruited by recruits based at Majengo.
Police have since established she was in Kismayu with Yassin where she received training on suicide bombing.
In the seizure of the suicide vests, each of the suicide bombers was to carry at least three hand grenades, besides wearing a specially made vest laden with explosives.
Investigations show they were to be escorted by men with AK-47 assault rifles who would also be carrying two extra magazines. Each magazine carries at least 30 rounds of ammunition.
The plan was thwarted after officers from the Special Crimes Prevention Unit and Flying Sqaud raided a house in Eastleigh at around 1am on Friday and arrested Mr Abdimajid Yassin Mohammed alias Ali Hussein and Mr Omar Abdi alias Adan Salman Abdi.
Mr Mohammed pleaded guilty when he was charged with nine terrorism counts, while Mr Abdi denied having committed the offences.
The gunmen were also to open fire at police officers in order to force their way past security checks so as to reach politicians.
The Scotland Yard detectives and those from Israel have been holding meetings at the ATPU headquarters since the terror plan was unearthed.