Police said they would be questioning her tenants, with whom she was locked in a court dispute over her property.
During investigation, it was found that several similar incidents of cheating and theft had earlier been reported from the area.
32-year-old arrested, police say he knew woman, called her to TGIP for a ‘job interview’.
A total of 16 people have been arrested in connection with the two FIRs by the Crime Branch so far.
Police are now trying to ascertain the identity of the people who approached Singh for fake IDs.
Police suspect that he was procuring documents from other ministries as well.
More arrests are likely soon as search and raids are continuing in Delhi and NCR in this connection.
Sources said he quit in 2011, and joined Jubilant Energy as a senior executive the next year, with a monthly salary of Rs 1.5 lakh.
Police sources said the probe would be widened and petroleum ministry officials may be called in for questioning soon.
RIL has a series of ongoing arbitration actions against the government.
Prayas Jain and Santanu Saikia were taken into custody by Delhi Police Crime Branch today.
Police Commissioner B S Bassi said official documents were photocopied and leaked in return for money.
Five arrested including an RIL man and two Petroleum Ministry employees, more arrests likely.
More than 7 incidents, including ire, theft, alleged arson, have been reported in churches over last 3 months.
Since the couple had been married for only a few months, an SDM inquiry has been initiated into the matter.
The PM has directed Delhi Police Commissioner to take strict action against perpetrators of such attacks.
Among the five persons who were questioned along with Tharoor were his two domestic helps, Bajrangi and Narain.
Delhi Cantt recorded 69.68 per cent turnout on Monday, with 632 out of 907 registered voters.
Voters in Mangolpuri and Sultanpur Majra seemed to have warmed up to the Congress.
The former CM also questioned the AAP on the source of its funding.