Alleged smugglers returned money to silence asylum seekers who escaped a fishing boat that sank drowning hundreds of people, a court has heard.
The testimony was heard in the committal hearing of Iraqi national Maythem Kamil Radhi who is accused of involvement in a syndicate that put hundreds of people on an allegedly overcrowded and dilapidated fishing boat known as SIEV-X in 2001.
The scheme involved the attempted smuggling of 421 people, ending with 353 drowning, 146 of them children.
Radhi, 45, is not charged over the deaths, but faces one count of bringing groups of non-citizens into Australia, while two men have already been imprisoned for their involvement.
After the boat sank the smugglers assumed if they gave money back to some families no one would talk to police, Fawzi Al Majid told the hearing in Brisbane Magistrates Court on Tuesday.
Mr Al Majid said he had paid $1000 to Radhi and another man to take part in the operation.
But after the boat sank some money was paid back by a third man.
"They assumed if they give us the money we won't talk anything to the police," Mr Al Majid, testifying by video-link, said through an interpreter.
"Many people died from that accident and they want to shut the people's mouth with this money."
The case against Radhi suggests he played a "facilitation" role before the ill-fated voyage left Indonesia, commonwealth prosecutor Daniel Caruana said at the start of the hearing.
Some witnesses say he was present when money was negotiated, but they "more consistently" remembered him as an organiser, Mr Caruana said.
Much of the allegation centres on taking care of logistics, including buses between hotels and beaches.
Mr Al Majid said hundreds of people were taken by bus to a hotel in Sumatra where they spent four days waiting for the boat.
But there were up to eight rooms only for women and children so the men stayed in the hotel grounds, he told the hearing.
The committal hearing continues.