The Goa crime branch has launched an extensive investigation, covering senior government officials, into the alleged illegal mining case involving NCP general secretary Jitendra Deshprabhu.

The investigation covers senior government officials, including the mines and geology director, forest conservator, Goa state pollution control board chairman and even the state transport director who all have been accused of shielding illegal mining in Goa, police said.

"We will be quizzing almost everyone associated with this case," deputy superintendent of Police Chandrakant Salgaoncar said adding that an FIR has been registered against Deshprabhu, besides senior government officials on May 11.

Deshprabhu, whose family owns huge tracts of land in North Goa's Pernem taluka, has been accused of indulging in illegal mining to the tune of Rs 50 crore.

The crime branch had on Wednesday interrogated the director of mines and geology department, Arvind Lolienkar, who is also responsible for giving a mining licence, in connection with the case.

The interrogation went on for almost seven hours at the office of the crime branch at Dona Paula.

Deshprabhu's alleged illegal mine was discovered in 2007 and subsequently the issue was raised in the Goa legislative assembly by opposition benches, led by the BJP.

The mines department had also initiated inquiry into the mine, which according to them, had already exported several thousand tones of ore, without proper licence.

The department had found 15,000 metric tones of ore stacked at a site reportedly owned by Deshprabhu's family.

Salgaoncar said that Deshprabhu was issued summons to remain present before the investigating authority on Wednesday, which he ignored.

The crime branch has now decided to issue summons to Deshprabhu only after questioning the state government authorities responsible for regulation of mining in the state, he said.