I have done an internet search for you. Billie Jean was a mentally ill female, who used to hang around Michael Jackson. And claimed he had made her pregnant.
The song's lyrics refer to a real-life experience, in which a mentally ill female fan claimed that Jackson fathered one of her twins.
a young woman wrote a letter to Jackson, informing the singer that he was the father of one of her twins. Jackson, who regularly received letters of this kind, had never met the woman in question and ignored it. The woman sent more letters to Jackson, claiming that she loved him and wanted to be with him. She wrote of how happy they would be, bringing up the child together. She pondered how Jackson could ignore his own flesh and blood(his "child")The letters disturbed the singer to the extent that he suffered nightmares.
Following the letters, Jackson received a parcel containing a photograph of the fan, as well as a letter and a gun. Jackson was horrified–the letter asked that the pop star kill himself on a certain day and at a specific time. The fan would do the same once she had killed their baby. She wrote that if they could not be together in this life, then they would be in the next. To his mother's dismay, Jackson had the photograph framed and hung above the dining room table of their family home. Afterward, the Jacksons discovered that the female fan had been sent to a psychiatric hospital.this female came in mind when he wrote billie jean.
he talks about the court case(for 40 days and for 40 nights,the law was on her side)
the lady shows alot of interest in michael,and beleives he is the father of her child (I said dont mind but what do u mean, I am the one)