Dr. Conrad Murray, who was Michael Jackson's personal physician, is refusing to testify in the wrongful death lawsuit that the singer's mother filed against concert promoter AEG Live.
If called, he will plead the fifth so as not to incriminate himself, the doctor said in a statement sent to the Jackson family.
Murray has never been questioned under oath about Jackson's death which occurred on his watch.
He did not testify at his trial, where he was found guilty of causing Jackson's death on June 25, 2009, by administering a deadly overdose of sedatives and the surgical anesthetic propofol in what he told police was an attempt to cure the singer's insomnia.
He is serving a four-year sentence but could be out in two.
On Monday, he was supposed to be deposed in the wrongful death suit.
But lawyers for Jackson's mother, Katherine, and her three children called off their jailhouse visit because Murray swore "he would not answer any questions at the deposition or the trial," Jackson lawyer Kevin Boyle told CNN.
He said the Jackson case would not suffer without his testimony.
AEG's lawyer suggests the Jacksons canceled Murray's deposition because his testimony would "destroy" their case.
"They are not interested in the truth," said the lawyer, Marvin Putnam.
Asserting his 'Fifth Amendment privilege'
The cancellation came after Murray's attorney Valerie Wass sent the Jacksons a sworn statement signed by Murray making it clear he would not answer any questions while his involuntary manslaughter conviction in Michael Jackson's death is being appealed.
"Accordingly, if I am called or ordered to testify at deposition or trial in the Katherine Jackson vs AEG wrongful death case, I will be asserting my Fifth Amendment privilege against self-incrimination and refuse to answer any questions," Murray's declaration said.
Jury selection in the civil trial is set to begin April 2 in a Los Angeles County court.
Prince Jackson, the pop star's oldest son, is expected to testify about his father's last days.
Jacksons: Focus back on AEG
The Jackson lawsuit contends that AEG Live is responsible for Jackson's death because it hired and supervised Dr. Murray, who was administering the surgical anesthetic propofol to Jackson each night for a month to induce sleep as he prepared for a series of concerts organized by AEG Live.
A jury found Dr. Murray guilty of involuntary manslaughter after hearing testimony that he violated medical standards in his treatment of Jackson.
"Dr. Murray's choice to keep quiet puts the focus back on the company -- AEG -- that hired Dr. Murray and agreed to pay him over $1.5 million a year, and provide Murray with a large house and drivers and other perks, to make sure that the company's biggest asset, Michael Jackson, made it to the shows on time, no matter what," Boyle, the Jacksons' lawyer said.
The judge ruled last month that Jackson lawyers could question Murray at the Los Angeles County jail, where he is serving his prison sentence.
AEG: Testimony destroys Jacksons' claim
"The Jacksons told the world that they wanted Dr. Murray's deposition, and then when the Court gave it to them, they canceled it," Putnam, the AEG lawyer, told CNN on Sunday.
"They have had all of their claims dismissed except negligent hiring, and they don't want Dr. Murray to be deposed because he will tell them what he already told the police -- that he worked for Michael Jackson; that Michael Jackson, not AEG, was his employer; and that Michael Jackson personally invited him to join the 'This is It' tour long before anyone at AEG had even heard of him. The Jacksons canceled the deposition because that testimony destroys the only claim they have left. They are not interested in the truth."
Back and forth
The Jacksons' lawyer argued, in response to Putnam's comment, that AEG was not interested in having Murray take the stand in the trial.