This is the second judgment by the special courts set up at the MP Hostel in Sher-e-Bangla Nagar in the capital for quick disposal of the corruption cases.

"The sentence shall take effect at once," said Fifth Special Court Judge Ashraf Hossain.

After the conviction, Mamun's counsel barrister AKM Fakhrul Islam said, "We will file an appeal in the High Court against the verdict."

The same judge's court on May 21 gave first judgement of the special court and sentenced Harris Chowdhury, political secretary to former prime minister Khaleda Zia, to three years' imprisonment for not submitting his wealth statement to the ACC.

Mamun, now in jail, was produced before the court yesterday while the judge read out the written judgment.

Mamun, who was shown arrested on March 26 in an extortion case, told the special court on May 29 that he could not submit his wealth statement in time as he was in the joint forces' custody from January 31 to March 26.

"I was in their custody between January 31 and March 26. After March 26, I was taken into their custody again, and kept on remand for 50 days. This is why I could not submit my wealth statement," Mamun told the court in his statement.

On February 18, the ACC directed Mamun to submit his wealth statement within 72 hours, but neither he nor any representatives on his behalf submitted the statement.

ACC official SMM Akhter Hamid Bhuiyan filed the case on April 5 with the sessions judge's court seeking an arrest warrant against Mamun for not submitting his wealth statement to the commission within the stipulated time.

The court on May 14 transferred the case to the Fifth Special Court that framed charges against Mamun.

In the case against Mamun, six witnesses including the complainant, ACC official Akhter, testified for the prosecution.

Judge Ashraf Hossain, who read out the judgment for more than an hour, said, "Having given due regard to the aforesaid provision of law coupled with the facts, circumstance and the evidence on record, I am led to believe and hold the view that the prosecution has been able to bring the charge home against the accused, who is found guilty."

Passing the order, he said, "that Md. Giasuddin Al-Mamun be convicted U/S (under section) 26(2)(Ka) of the Anti-Corruption Commission Act 2004 read with rule 15 (gha) (5) of the Jaruri Khamata Bidhimala, 2007 and he be sentenced to suffer simple imprisonment for three years U/S (under section) 26(2)(Ka) of the Anti-Corruption Commission Act 2004."

Mamun will get 30 days' time to appeal against the verdict in the High Court, prosecution lawyer AFM Gholam Fattah told The Daily Star.

Besides the non-submission case, Mamun is already facing 13 cases in different charges including extortion and arms cases.

The anti-graft body is preparing to file more graft cases against Mamun, sources said, adding that the investigators, working to find out his wealth in and outside the country, have already detected huge wealth of Mamun, but it will need more time to unearth his total assets.