Jakarta. A businessman in the center of what is arguably Indonesia’s biggest corruption scandal arrived at Soekarno-Hatta Airport after a flight from Taiwan on Monday to turn himself in to prosecutors after he was named a suspect in the case.

Surya Darmadi, the owner of major plantation company Duta Palma Group, is charged with corruption and money laundering for alleged illegal occupation of state-protected lands or forests covering more than 37,000 hectares.

According to the Attorney General’s Office (AGO), the crime has inflicted a loss of Rp 78 trillion ($5 billion) to the state.

Surya was aboard a China Airlines flight and arrived at the airport in the Jakarta’s suburb of Tangerang at 1:30 p.m. He was immediately taken by prosecutors for an interrogation, Attorney General Sanitiar Burhanuddin said at a news conference in Jakarta.

“We are currently interrogating the suspect who will be detained for at least 20 days,” Burhanuddin said.

Prosecutors have sent a warrant to three locations -- Duta Palma office in Riau, Surya’s residence in Jakarta, and his home address in Singapore -- and the suspect replied two weeks ago that he would cooperate and attend the questioning, he said.

An attorney for Surya said his client's arrival proves that he is cooperative with no intention to flee the ongoing legal proceedings.

"Our client Surya Darmadi aka Apeng has kept his promise of honoring the summons on the 15th and today he officially begins participating in the whole proceedings either at the prosecutor's office or other law enforcement agencies,” lawyer Juniver Girsang said.

He added that Surya is currently under medical observation but didn’t provide more details.

The lawyer took credit for Surya’s return, saying he had told his client that the defense team could do nothing if he remained at a foreign country and persuaded him to return.

Apart from the AGO, Surya is also a graft suspect in a separate land conversion case investigated by the Corruption Eradication Commission, or KPK.

The AGO said they are coordinating with the KPK in pursuing graft convictions for Surya.

Prosecutors accused Surya, Duta Palma Group, and the company’s subsidiary Palma Satu of illegally occupying state lands for personal and corporate gains.

Both companies reaped Rp 600 billion in monthly profit from doing business on the illegally-occupied lands, causing a total loss of Rp 78 trillion to the state, according to earlier AGO’s statements.

The Indonesian law allows business entities to become corruption suspects. Another suspect in the case is identified as Suheri Terta, the group’s legal affairs manager.

The group is also known as a major cooking oil producer under the brand Palma.

During the investigation, the AGO seized at least eight plantation areas operated by Duta Palma subsidiaries and partnering companies in the Riau district of Indragiri Hulu and froze their accounts in Bank Mandiri and Bank Central Asia.

In addition, prosecutors also seized 15 lands and buildings with links to the company and their executives in South Jakarta.

The AGO didn’t say when the suspected crime began but Surya is accused of conspiring with Raja Thamsir Rachman, the two-term district head of Indragiri Hulu in 1999-2008 who is currently serving jail term for misappropriating the district budget.