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NEW DELHI - The conviction of an Indian federal minister for abducting and murdering his aide 12 years ago has triggered a debate over the rising criminal element in national politics.

According to Lok Sabha, or India's elected lower house of Parliament records, nearly a quarter of the country's 545 MPs have a criminal record. Charges range from murder to rape, kidnapping and fraud.

Shibu Soren, head of the regional JMM party and a member of the Congress Party-led federal coalition, resigned as Coal Minister last week after a Delhi court found him guilty of conspiracy in the 1994 kidnapping and murder of his former private secretary, Shashinath Jha. Yesterday he was sentenced to life imprisonment and ordered to pay 500,000 rupees ($16,400) to the victim's family but he is to appeal. Prosecutors said Jha was killed for blackmailing the minister over bribe-taking.

Four others associated with Soren were also found guilty of murdering Jha and burying his body in Jharkhand's state capital Ranchi.

"Before we were trying to focus on the criminalisation of politics. Now we have the criminalisation of the council of ministers," Opposition leader Lal Krishna Advani said.

In the absence of any policy to ban criminally charged MPs, Prime Minister Manmohan Singh has drawn the line at criminal conviction.

He recently said the country needed a law to define the meaning of "criminal" and tighter controls on who can become a minister.

Some Indian MPs have even fought and won elections from jail.

According to a report by the National Social Watch Coalition, an alliance of social groups, parliamentarians, academics and policy makers, there had been a big rise in the number of people with criminal records contesting elections in India, further blurring the line between crime and politics.