A lawyer for Michael Jackson's father said Tuesday he intends to file a wrongful death lawsuit against the late pop star's doctor within 90 days, claiming the physician's actions amounted to murder.

Brian Oxman, who represents Joe Jackson, said the amount of the powerful anesthetic propofol given to the "Thriller" singer by Dr Conrad Murray before Jackson's death on June 25, 2009 "was reckless, and it amounts to second-degree murder."

"The continuous administration of drugs over six weeks -- he (Murray) gave him propofol every night -- that is Russian roulette, that is loading six bullets into a gun with only six chambers," Oxman told Reuters.

As part of a criminal investigation, prosecutors have charged Murray with involuntary manslaughter in the death of Jackson, 50, who had been rehearsing for a series of concerts in London before his death.

Murray had been hired by concert promoter AEG Live to care for Jackson in the months leading to the London shows.

The wrongful death lawsuit would be a civil lawsuit, which can run in parallel with the criminal suit. The criminal suit can result in a jail sentence whereas the civil lawsuit's main purpose is winning monetary damages against a defendant.

Los Angeles officials have ruled the death a homicide caused by "acute propofol intoxication" at a level that was equivalent to that used for anesthesia during "major surgery."

Jackson had been taking propofol for insomnia, and Murray has admitted administering the drug to him the day he died. Murray has said he did nothing wrong and has pleaded not guilty to involuntary manslaughter.

The singer also had other sedatives in his system including lorazepam which contributed to his death, the Los Angeles County Coroner has concluded.

Oxman said private investigators have been piecing together evidence and testimony, and his group has concluded that Murray bears responsibility.

He said California law requires anyone filing a wrongful death lawsuit to do so within one year of a person's death and to give the defendant 90 days' notice before the filing.

Oxman said Joe Jackson decided to notify Murray's lawyer, Houston-based Ed Chernoff, now to meet the one-year requirement because the anniversary of his son's death is 90 days away and because it has taken this long to gather evidence.

"Having records, instead of just speculation, has been very important and hard to do, but we (now) finally have the records so we can tell what happened," Oxman said.

A spokeswoman for Chernoff said he had not yet received the notice and would have no comment until he had seen it.

Oxman said it was not yet clear if other Jackson family members, including mother Katherine Jackson who is a beneficiary of her son's multimillion dollar estate, will join in the lawsuit.