Along with Tyagi, his cousin Sanjiv alias Julie Tyagi and lawyer Gautam Khaitan were also arrested.
Shah said the 'friendship' between Christian Michel, the alleged middleman in the deal, and Congress' top leadership is 'time tested and deep'.
Others named in the chargesheet include alleged European middlemen in the deal, Carlo Gerosa and Guido Haschke.
Uttam Ghosh/Rediff.com offers his unique perspective on several issues of the day.
The AgustaWestland VVIP chopper deal will once again dominate the proceedings in Parliament on Thursday.
India has encashed a guarantee of over Rs 250 crore deposited by AgustaWestland in a bank in New Delhi even as it is preparing to file an appeal against an Italian court's stay on its move to encash another guarantee deposited in an Italian bank.
Swiss authorities have arrested Guido Ralph Haschke, the alleged middleman in the AgustaWestland VVIP helicopter deal, on charges of bribery, Italian media reported.
Swaraj Abhiyan leaders Prashant Bhushan and Yogendra Yadav in Delhi accused the Raman Singh government of paying $1.57 million (Rs 10 crore) as 'commission' to a company registered in tax-haven British Virginia Islands to procure the chopper.
The Comptroller and Auditor General on Tuesday slammed the Defence Ministry and Air Force for "several instances" of deviation from rules in the procurement of VVIP choppers in the Rs 3,727 crore AgustaWestland deal.
Raising the issue during Zero Hour, Roy wanted to know who has taken bribe in the deal to buy 12 VVIP helicopters.
Prime Minister Manmohan Singh on Tuesday said that he conveyed India's concerns about the alleged unethical means used in securing the 2010 contract for AgustaWestland helicopters to British Prime David Cameron, and added that the latter has assured him of his government's cooperation in the investigations.
The bribery scandal involving AgustaWestland's VVIP helicopter deal threatens to corner the Congress party and cast a shadow on India's latest $10 billion defence deal with Dassault for 126 Rafale fighter aircraft. Vicky Nanjappa reports
With the latest AgustaWestland helicopter import scandal, it is time to re-examine the role of the ubiquitous but ostensibly banned defence agents, middlemen, intermediaries, brokers, consultants, weapon merchants or reps as they are variously known, says Rahul Bedi
The Central Bureau of Investigation on Monday questioned former Indian air force Chief S P Tyagi and two others in connection with alleged irregularities in the AgustaWestland helicopter deal.
For a man revered for his probity, Defence Minister A K Antony was caught napping when bribes were paid over the AgustaWestland VVIP chopper deal. With the UPA government staring at another scam, nothing it seems will change, writes Sheela Bhatt.
Arriving in New Delhi within days of exposure of the Rs 3,600-crore VVIP helicopters scam involving Anglo-Italian firm AgustaWestland, British Prime Minister David Cameron is likely to be pressed for more information in this regard during his meetings with the leadership on Tuesday.
Cracking the whip, India on Friday initiated action to scrap the deal for purchase of 12 VVIP helicopters from Italian firm AgustaWestland in the wake of allegations that kickbacks to the tune of Rs 362 crore were paid to bag it.
The deal to procure 12 VVIP choppers for the IAF is under scanner as an American-Italian person is being investigated for allegedly paying kickbacks for securing the deal for Agusta Westland.
Amid the storm over alleged kickbacks in the AgustaWestland VVIP chopper deal, Comptroller and Auditor General Vinod Rai on Friday said an audit of the controversial deal is under progress and a report would be released soon.
Armed with fresh details on the alleged kickbacks, India has initiated steps to cancel the Rs 3,600 crore-chopper deal with Anglo-Italian firm AgustaWestland by issuing a show cause notice to it in this regard.
The agency questioned him on various aspects of the case including his alleged links with middlemen, his alleged trips to Italy, reasons behind changing specifications, and relations with his cousins on Monday, the sources said.
A special court denied Christian Michel bail in the related Central Bureau of Investigation case.
'We will continue to ask why Modi and his government were benefactors to this AgustaWestland company, why within 40 days they overturned the ban?'
The former board member of Aeromatrix, which was allegedly used to route bribe amount, denied the payments were part of kick backs to clinch the deal.
A Delhi court on Saturday sent former Air Force Chief S P Tyagi, arrested in Rs 450 crore Agusta Westland bribery case in procurement of 12 VVIP helicopters, to police custody for four days after the CBI said he was needed to be quizzed to unearth a "very large conspiracy having international ramifications".
With an aggressive Opposition and unyielding government, important legislation could be the biggest casualty, as details of the helicopter contract surface.
The Central Bureau of Investigation will soon approach United Arab Emirates authorities seeking extradition of British national and alleged middleman Christian Michel James in connection with its probe in the Rs 3,600 crore AgustaWestland VVIP choppers deal.
Italian prosecutors have "shelved" proceedings against defence major Finmeccannica, the parent firm of AgustaWestland, saying it had nothing to do with the alleged corruption in India's Rs 3,600-crore deal to procure 12 VVIP helicopters, Italian news agency Ansa reported.
He was subjected to a marathon 10-hour questioning on Thursday by ED investigators.
In a bid to corner the Congress after it launched a tirade against it for imposition of President's rule in Uttarakhand, the ruling dispensation has decided to raise issues of AgustaWestland Chopper scam, Aircel Maxis scam and the Ishrat Jahan case in the Parliament on Wednesday.
CBI had registered a case against Tyagi along with 13 others including his cousins and European middlemen in the case.
The Congress on Monday sought a discussion on the latest report of the CAG, listing alleged irregularities in Gujarat State Petroleum Corporation's KG basin gas project and forced three adjournments in Rajya Sabha in the pre-noon session demanding a response from Prime Minister Narendra Modi.
The CBI argued before the high court that each day Tyagi remained out on bail would lead to its line of investigation being "exposed" and "hampered" and the evidence could also be destroyed.
India has received a fresh tranche of crucial documents from Italy in connection with Rs 3,600 crore VVIP helicopter deal which is likely to help Central Bureau of Investigation in expediting the probe into the bribery scam allegedly involving the then Indian Air Force chief S P Tyagi.
The Central Bureau of Investigation will soon examine army officers who were part of the selection process for the 197 light utility helicopter deal which came under scanner of Italian authorities during their probe into bribery allegations against AgustaWestland in VVIP helicopter agreement.
Carrying on with its probe into allegations of over Rs 360 crore bribe paid in the purchase of VVIP helicopters, the Central Bureau of Investigation recorded statement of Goa Governor B V Wanchoo as a "witness".
"Many people who had some links with Agusta, I am not saying illegitimate links, but some links with Agusta procurement and supply, were given good positions," Parrikar told PTI in an interview.
Michel was arrested in the United Arab Emirates and extradited to India on December 4.
A high-level team headed by defence ministry's director general (acquisition) today left for Italy to go through the crucial documents and evidence provided to India by the government there in the Rs 362 crore VVIP chopper scam.