Lucknow, Dec. 22: A regional food controller has been formally arrested in connection with the murder of an auditor who had blown the whistle on a massive diversion of food grain meant for the poor to the markets.

The killing of a key witness in a scam said to be running into several thousand crores has thrown light on a complex web involving government officers, contractors and mafia attempting to thwart investigation into the case.

Sailendra Singh, the regional food controller of Lakhimpur Kheri district, was picked up from Moradabad on Monday and formally arrested yesterday. Earlier, two contractors had been arrested.

The body of D.K. Shukla, auditor of the food and civil supplies directorate in Lakhimpur Kheri, was found with open wounds near Gurubuxaganj of Rae Bareli on November 8, said special superintendent of police V.P. Srivastava.

Police identified the body and got a whiff of the plot behind the murder from two documents found in his pocket. One was a copy of the complaint he had sent to the higher authorities on the irregularities in the food directorate.

?After month-long investigation, we have arrested the regional food controller of Lakhimpur Kheri, Sailendra Singh, and two contractors, Mithilesh Singh and Rajkumar Gupta. The auditor?s refusal to withdraw a complaint on food distribution irregularity apparently prompted the accused persons to kill the auditor,? Srivastava said.

?The case has thrown up names of important government officers and the sinews of conspiracy would come to light once the investigation is completed,? he added.

Sailendra Singh is said to have told the police that he had invited Shukla to a hotel in Lucknow to persuade him to withdraw the complaint. When he refused, he was locked up in a room and beaten, leading to his death. The body was later dumped in Rae Bareli.

Shukla had written that of the 1,500 quintal of food grain meant for distribution in one block in a work season (Feb-May), 750 quintal would be sold in the market, netting Rs 50 lakh every month for the culprits. Fake vouchers and receipts were manufactured to cover up the misuse. Irregularities in Lakhimpur Kheri are believed to be worth over Rs 100 crore.

Similar scams have been reported from mostly the eastern and central districts like Mau, Ballia, Azamgarh, Gazipur, Gorakhpur, Basti, Gonda, Barabanki and Lucknow.

The food grain are collected from the Food Corporation of India for distribution in the food-for-work programme ? where labourers are rewarded in kind for work on development projects ? under the Antodaya Yojna. The regional food controller collects the grain and hands it over to the district rural development authority, which chooses the areas for distribution.

The CPI first made noises against the irregularities early in November, comparing it with the fodder scam in Bihar and demanding a CBI probe. If the figures tumbling out are confirmed, it could prove to be bigger.

Now, the Congress has joined it. ?With such a sensational development in the case, we believe only a CBI probe can do justice,? said Congress spokesperson Akhilesh Singh.