The Palmolein graft case, which took another surprising turn with a vigilance court ordering probe into the alleged role of Kerala chief minister Ommen Chandy in his capacity as finance minister in early 1990s, has been a political spectre that keeps revisiting Congress in the state for the last two decades.

The case shook Congress stalwart K Karunakaran when he was at the height of his power as chief minister and a member of the Congres working committee and the party's central parliamentary board.

While he was battling the Palmolein scam, Karunakaran was caught in the vortex of the infamous "ISRO spy scandal" and they together led to his mid-course resignation as chief minister in 1994.

The scandal related to the allegation of espionage against an ISRO scientist, which the CBI found to be false.

More recently, the appointment of P J Thomas as the Central Vigilance Commissioner was quashed by the Supreme Court as he continues to be an accused in the Palmolein case as food secretary in Kerala when the deal took place in 1991.

A serving IAS officer, a couple of retired bureaucrats, in their seventies, and former minister and Congress leader T H Mustaffa are among those listed as accused in the case.

The scandal pertained to alleged loss caused to the state exchequer to the tune of Rs 2.32 crore by import of 15,000 tons of palmolein from Malaysia through a Singapore-based trading firm.

The scandal surfaced in 1993 with the Accountant General's report finding that the import of palmolein caused a loss of over Rs 2 crore to the exchequer and cast serious doubts about the way the decisions to clinch the deal had been taken.

The LDF Government that came to power in 1996 ordered the vigilance probe into it and the FIR was submitted to the court next year.

In 2001, the vigilance court ordered that prosecuting Karunakaran in the case required permission of the Lok Sabha Speaker as he was a member of parliament at the time. The Kerala High Court, however, gave nod to the vigilance to go ahead with prosecution of Karunakaran but that order was quashed by the apex court later.

In 2005, the UDF government headed by Oommen Chandy decided to wind up the case. But the case was revived by the LDF ministry headed by V S Achuthanandan in 2006.

With the death of Karunakaran last year, his plea pending in the Supreme Court against initiating prosecution proceedings became invalid, leading to the start of the trial in the case.

It was at this juncture that Chandy's name figured afresh.

Claiming high moral ground, Chandy offered to step down as chief minister after the vigilance court ordered the probe on August 8, however he was dissuaded by Congress heavyweights and leaders of the UDF constituents.

The UDF argument was that the palmolein issue had been discussed many times in the state Assembly and it had several legal turns but never had any allegation been levelled against Chandy by political rivals on those occasions.