Michael Jackson refused offers of help from his worried family, who believed he was addicted to painkillers, a court heard.
The superstar (inset) said that he did not have a drug problem, the Los Angeles court heard.
Police detective Orlando Martinez said Jackson's mother Katherine had told him that the family tried drug interventions for the singer.
The testimony came under questioning by lawyers for concert promoter AEG Live, which is being sued by Katherine Jackson for negligence in the star's death.
Mr Martinez, who led the investigation into Jackson's death in June 2009, said he first interviewed Jackson's mother at the hospital.
But six months later, he decided to go back to her and check out "some things regarding family meetings about addiction".
He said it was then that she told him about several attempts by the family to get Jackson into rehab.
"Mrs Jackson said the family tried to help him but he would have nothing to do with it," Mr Martinez said.
"She had asked Michael if he was taking any drugs, and he denied it."
He said Katherine Jackson told him she believed her son was taking medicine for back pain and might have become addicted.
Katherine Jackson also told him that the first time she ever met Dr Conrad Murray was at the hospital the day her son died. Murray was convicted of involuntary manslaughter after giving the anaesthetic propofol to the pop star.
Katherine Jackson's lawsuit claims AEG did not properly investigate Murray.
AEG denies it hired the doctor, and it is likely to blame Jackson for insisting on having Murray as his doctor because of his dependence on propofol.