N B Singh, who was posted in the Lucknow office of the ED, along with middleman Subhash was allegedly threatening to attach the properties of the accused.
They were demanding a bribe of Rs 50 lakh to take a lenient view of the matter.
The officer was on May 18 relieved by the Enforcement Directorate but he continued going to office, sources said.
A trap was laid by the CBI and the duo were arrested while allegedly taking Rs 4 lakh as a part payment of the bribe.
The ED is also considering registering a money laundering case against him.
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