Handwritten notes written by Michael Jackson in the weeks before his death reveal the singer feared he would be murdered.

The music icon died in his Los Angeles home in June 2009 after suffering a heart attack. He was 50.

In the messages he said: "They are trying to murder me" and "I am scared about my life."

In an interview with broadcaster Daphne Barak for Australian TV show Sunday Night, German businessman Michael Jacobshagen revealed the existence of 13 letters written to him by the singer.

Jacobshagen, who was friends with the star for two decades, told Barak that Jackson called him from a Las Vegas hideaway in tears.

The star was in the throes of rehearsals for his ill-fated This Is It tour at London's O2 Arena but pleaded with his friend to fly from Germany to the US to help him.

Jacobshagen went to the US to spend three days with the singer who handed him the notes in which he said "they" were trying to murder him.

"He was in emotional meltdown saying, 'They are going to murder me'," Jacobshagen said.

Some of the notes make reference to concert promoters AEG, which was behind the This Is It tour. "AEG. Make so much pressure to me... I'm scared about my life," Jackson wrote.

Just weeks later, he was found dead.

According to the coroner's report he died from an overdose of the sedative propofol. Jackson's doctor, Conrad Murray, was found guilty of the star's manslaughter after administering the powerful anaesthetic to Jackson hours before he died. Murray served two years of a four-year jail sentence.

Jacobshagen claimed that Jackson had been using propofol for more than 10 years to treat insomnia and reportedly questioned what might have been behind his untimely death.

Total conspiracy theory

He added that he decided to go public with the notes to support Jackson's daughter Paris, 19, who recently claimed her father was murdered.

Opening up about his death in an interview with Rolling Stone magazine, she said: "He would drop hints about people being out to get him. And at some point he was like, 'They're gonna kill me one day'.

"It's obvious. All arrows point to that. It sounds like a total conspiracy theory and it sounds like b******* but all real fans and everybody in the family knows it. It was a setup. "

Jackson's sister LaToya has also previously expressed her belief that the Thriller singer was unlawfully killed.

The interview will be broadcast next month to coincide with the anniversary of the star's death, Mail Online reports.