Superstar Michael Jackson sexually abused a young cancer patient and showed him pornographic material on the Internet, a Californian court was told yesterday.

As the trial of the pop singer finally began yesterday, District Attorney Thomas Sneddon said that Jackson showed the boy - then aged ten - adult material on various websites at his Neverland ranch in 2000.

But a series of bizarre activities alleged to have been carried out were also revealed in an indictment read to the jury by Superior Court Judge Rodney S Melville, detailing a conspiracy over the molestation of the boy at Jackson's ranch and a supposed attempt to keep his family silent.

The indictment stated that, between February and March 2003, Jackson's employee Frank Tyson, also known as Frank Cascio, threatened the boy, telling him "Michael could make the family disappear" and "I could have your mother killed".

It also alleged a panicky effort by Jackson employees to get the family of his accuser ready for a trip to Brazil, with It alleged that Tyson told the family they were in danger and "this is not the time to be out there alone. This is not the time to turn your back on Michael".

It also alleged that, in February 2003, Jackson's staff was instructed in writing not to let the boy leave Neverland.

Also named as unindicted co-conspirators were fellow Jackson employees Ronald Konitzer, Dieter Wiesner, Marc Schaffel and Vincent Amen.

Mr Sneddon said that in August 2000, Jackson invited the child and his family to Neverland. At dinner during the first visit, Sneddon said, Jackson told the child to ask his mother if he could sleep in Jackson's bedroom and the boy did.

That night, he said, Jackson took the boy to his bedroom along with Tyson and Jackson's own son, Prince Michael.

On that night, he said, Jackson took the boys on a 45-minute tour of sexually explicit websites with naked bodies.

When an image of a woman with bare breasts came on the screen, Mr Sneddon said, Jackson turned to the group and said: "Got milk?".

Mr Sneddon referred to the boy by name, telling the court it would be impossible to proceed without using his real name and his family's.

Mr Sneddon told the jury the case was about Jackson's desperate attempt to save his career after the British TV documentary Living With Michael Jackson, in which he was seen holding hands with the boy and saying he allows children to sleep in his bed.

Jackson had intended to exploit the boy by using the documentary to demonstrate how the singer helped him through his cancer, Mr Sneddon said, and that Jackson told the boy what to say.

But Mr Sneddon said "Jackson's world was rocked" when the documentary, shown in early 2003, backfired and created negative publicity, leaving Jackson's team trying to get the boy and his family to deny suggestions of abuse.

The prosecutor said the molestation occurred after those events, in February or March 2003, when the boy was 13. He described two incidents, including one when Jackson reached into the boy's underpants and masturbated the boy and himself.

The defence has described Jackson as the target of a money-hungry mother, who coached her son to spin stories when it looked like their celebrity benefactor would cut them off. The defence will present evidence that the mother has sued others in the past, claiming abuse.

Jackson arrived at court with a throng of news media watching, and was greeted by a handful of fans.

Mr Sneddon said Jackson was "heavily in debt" for years before the making of the documentary, drawing an objection from defence attorney Thomas Mesereau Jr. The judge sustained the objection, saying he had not ruled on whether financial evidence would be allowed.

He told jurors the child had undergone surgeries to remove a 16lb tumour from his stomach. His gall bladder and lymph nodes were also removed.