Former Punjab chief minister Charanjit Singh Channi was questioned by the ED for over six hours in a money-laundering investigation linked to sand mining in the state, officials said on Thursday.

The federal agency recorded the statement of the 59-year-old Congress leader under the Prevention of Money Laundering Act (PMLA) and he left the Enforcement Directorate's (ED) zonal office in Jalandhar late on Wednesday night.

Channi tweeted to say he was "summoned by the ED yesterday regarding the mining case".

"I attended and replied to the queries put by them to the best of my knowledge. A challan in this case has already been presented by ED in the Hon'ble court. The authorities have not asked me to come again," he posted on the social media platform.

Channi's nephew Bhupinder Singh alias Honey was arrested in this case by the agency days before the February 20 Punjab Assembly polls.

A charge sheet was filed against him and others before a special PMLA court in Jalandhar on March 31. Honey, currently lodged in judicial custody, has recently applied for bail.

According to sources, the agency questioned Channi, who had earlier skipped a few summons, about his links with Honey and others and about certain visits his nephew made to the chief minister's office.

He was also questioned about the allegations of certain transfer and posting of officials in the state as part of the illegal sand mining operations, the sources said.

Without naming anyone, former Punjab Congress chief Navjot Singh Sidhu tweeted, "My fight was for Punjab and not for sand. Those who ran the land, sand and liquor mafia let down Punjab for selfish vested interests by looting the exchequer. It is either Punjab or the mafia in the present financial scenario! The fight continues."

Channi resigned as the Punjab chief minister after the counting of votes on March 10 as the Aam Aadmi Party (AAP) swept the state polls.

The Congress leader also lost the electoral battle from both the Assembly seats he contested -- Chamkaur Sahib and Bhadaur.

The ED action in the case began on January 18 after it conducted raids against Honey and others and seized about Rs 7.9 crore cash from his premises and about Rs 2 crore cash from a person linked to him, identified as Sandeep Kumar.

The agency had said that it recorded statements of Kudratdeep Singh, Honey, his father Santokh Singh and Sandeep Kumar during the searches and it was "established" that the seized Rs 10 crore "belonged to Bhupinder Singh".

"Further, Bhupinder Singh accepted that he received the seized cash in lieu of facilitation in sand mining operations and transfer/postings of officials," the ED had claimed in a statement.

It had said Honey had appeared before it for questioning before his arrest and tendered his statement, wherein he stated that he is involved in the mining-related activities but took an evasive approach when confronted with incriminating data.

Honey, Kudratdeep Singh and Sandeep Kumar are stated to be the directors of a company, called Providers Overseas Consultants Pvt Ltd, which was raided by the ED in January.

The money laundering case was filed by the ED in November last year after taking cognisance of a Punjab Police (Rahon police station, Shaheed Bhagat Singh Nagar) FIR of 2018 that pressed charges under various sections of the Indian Penal Code and the Mines and Minerals (Regulation of Development) Act, 1957 to probe allegations of illegal sand mining.

In this police FIR, the ED said, it was mentioned that a team comprising officials of mining department, civil administration and police conducted a surprise check in March 2018 based on a complaint received at the Rahon police station regarding illegal sand mining.

"Consequently, it was found that several mines were being excavated by various machines and mining was being carried out beyond the designated area," he said.

"Accordingly, several tippers/trucks, porcelain machines, JCB machines, etc., were captured and seized by the investigating team. The seized tipper or trucks were also found to be overloaded with sand," the ED said quoting the police FIR.

The seized weighment slips having office stamps had not been issued by the office concerned and were forged. Subsequently, the mining operation at Malikpur mining site, allocated to Kudratdeep Singh, and the approval of weighment slips were stopped by the team, it said.

According to the FIR, the ED said, apart from Malikpur, illegal mining activities were also carried out at Burjtahl Das, Barsal, Lalewal, Mandala and Khosa.