An amount to the tune of Rs 2.5 lakhs per month was being paid to the two accused, Lalta Prasad and Rakesh Kumar, who were the first to be arrested outside Shastri Bhavan in New Delhi, it said.
Shailesh Saxena from Reliance Industries Limited (RIL), Vinay Kumar from Essar, KK Naik from Cairns India, Subhash Chandra from Jubilant Energy, and Rishi Anand from Reliance Anil Dhirubhai Ambani Group (Reliance ADAG), energy consultant Prayas Jain, and journalist Shantanu Saikia used to pay the amount to them, the charge sheet said.
"On sustained interrogation, they all admitted that they had hired the services of Rakesh Kumar and Lalta Prasad for obtaining the stolen documents of MoPNG for their business gains," it said.
The Crime Branch of the Delhi Police also did not rule out the possibility of slapping the charges under the Officials Secret Act (OSA) saying that reports pertaining to all the documents have not been received yet from the MoPNG and they have sought further clarifications from the ministry about it.
"The reports received on April 10, April 15, and April 16, 2015 from MoPNG have been analyzed and it has been observed that reports pertaining to all the documents have not been received.
"Further, it has also not been specified as to the documents marked as secret/confidential are covered under OSA or not. Further clarification in this regard is being sought from MoPNG," Delhi police said in its charge sheet filed against 13 arrested accused.
On Monday Chief Metropolitan Magistrate Sanjay Khanagwal took cognizance of the charge sheet and fixed the matter for further hearing on May 18.
Police said according to ministry reports, documents recovered from the accused were not in public domain and some of them were marked as "secret/confidential in nature."
It also said that due to the conspiracy hatched by the accused, "interests of the government and public at large have been compromised. The accused have been indulging in this cheating affecting public/national interest for many years."
Investigation regarding the role of senior officers and companies was in progress to ascertain their involvement, if any, it said, adding a supplementary charge sheet would be filed later.
Detailing the money transactions, police said that "analysis of bank statements of Lalta Prasad and Rakesh Kumar revealed that there were significant transactions by cash and cheques despite the fact that they were unemployed."
"The money tranactions in their accounts shows that they have procured that money by illegally selling the documents of MoPNG to various prospective buyers of the companies engaged in Petroleum and Gas sector.
"Assistance from chartered accountants has been sought to further analyze the detailed bank statements of the accused persons/companies. Outcome of which will be filed through the supplementary charge sheet," it said.
With regard to the documents being allegedly recovered from the possession of the accused people, it said that 80 sets of documents pertaining to MoPNG were seized from Mr Saikia's house and office while 50 sets of documents were seized from Mr Saxena's office.
It said seven sets of documents were seized from Mr Jain's office while four sets and nine sets of documents were seized from the offices of Vinay Kumar and KK Naik respectively.
Similarly, four and six sets of documents were recovered from Rishi Anand and Subhash Chandra respectively. Some of the other arrested accused were also found in possession of certain incriminating documents.
Most of the documents recovered from Mr Jain were not in public domain and six of these documents were marked secret /confidential, it said, adding, 23 documents seized from Mr Saikia were also marked as secret/confidential.
Similarly, two documents recovered from Mr Naik were marked secret whereas documents seized from Vinay, Anand and Mr Chandra were not marked as "secret/confidential".
Mobile phones, laptops / computers, and backup of e-mail account data of senior officials of Cairn India, RIL, Reliance ADAG, Jubilant Energy Pvt Ltd and Essar were taken into possession for examination and forensic opinion and result was awaited, police said.
It also said call detail records (CDR) of accused showed that they were in constant touch with each other over phone.
"Moreover, it is pertinent to mention that CDR analysis reveals that on many occasions the position of the accused was found to be in cell ID of MoPNG even during odd hours at night when they used to criminally trespass and steal the documents," the charge sheet said.
Referring to the ministry report, police said none of the documents recovered from the possession of Lalta Prasad was in public domain and two sets of documents were marked as secret CCEA note.
It said Mr Prasad, Rakesh Kumar and accused Raj Kumar Chaubey were not authorised to possess the documents recovered from their possession.
Police said Mr Prasad and Rakesh Kumar with connivance of co-accused Asharam, Ishwar Singh and Virender Kumar had obtained fake temporary I-card/pass of Audit Department defence service and MHA for gaining access to MoPNG and they had also got prepared duplicate keys of the offices.
Police said the accused had "lured" one Mr Vir Singh, who was a CCTV operator in the MoPNG, to switch off the cameras installed in the ministry to facilitate their movement in the office during night.
It said that the outcome of the probe regarding the alleged role of Mr Singh may be filed through supplementary charge sheet.
Police said a "deep rooted conspiracy" was hatched among the accused and the five corporate executives, Mr Jain and Mr Saikia were also the "perpetrators and conspirators" and they had provided the financial aid for carrying out the illegal activities.
It said ministry reports have been enclosed with the charge sheet in a sealed cover and its confidentiality should be kept.
All the accused have been chargesheeted for the alleged offences under sections 457 (trespass), 380 (theft), 411 (dishonestly receiving stolen property), 418 (cheating a person whose interest the offender was bound to protect), 420 (cheating), 468 (forgery for the purpose of cheating), 471 (using as genuine forged documents), 474 (possessing forged documents with intent to use it as genuine), 34 (common intention), read with 120-B (criminal conspiracy) of the IPC.
All the accused are currently in judicial custody.
On February 20, police had arrested the five corporate executives alleging that they used to procure the classified documents from Lalta Prasad and Rakesh Kumar and used to pay them.
The documents were then supplied to the firms by these officials for their benefit, the police had alleged.
The police had earlier told the court that sensitive documents of Ministries of Coal, Power and others were recovered during the investigation.
In its FIR, the police had said that photocopies of sensitive documents including inputs on the Finance Minister's budget speech were recovered from the possession of accused Rakesh Kumar.
A total of 16 people have been arrested so far in connection with two separate FIRs lodged by the Crime Branch.