Los Angeles (CNN) -- Michael Jackson's nephew testified Thursday that he believes his uncle was murdered.
T.J. Jackson, the youngest son of Jackson brother Tito, revealed his suspicion while being cross examined by an AEG Live lawyer in the Michael Jackson wrongful death trial.
Jurors also heard him testify about the emotional devastation caused by Michael Jackson's death.
"He was just everything," said T.J. Jackson, who shares guardianship of Michael Jackson's children -- Prince, Paris and Blanket -- with their grandmother.
Michael Jackson's mother and his children contend his last concert promoter was liable for his death because it hired, retained or supervised Dr. Conrad Murray, who was convicted of involuntary manslaughter.
AEG Live lawyers argue it was Jackson, not the company, who chose and controlled Dr. Murray. Their executives had no way of knowing he was giving nightly infusions of the surgical anesthetic propofol to Jackson, which the coroner ruled killed the singer, the lawyers say.
"Do you believe your uncle was murdered?" AEG Live attorney Jessica Stebbins Bina asked T.J. Jackson.
"I do," he answered. "I believe it because he did tell me and the brothers that he was going to be murdered on a couple of occasions.
"He said that just because of his position he was a target."
T.J. Jackson had earlier testified that his mother, Delores Jackson, was the victim of murder 19 years ago.
"My mother was murdered for money, too, so I don't put that past anyone," he said.
Initially it was believed that his mother, Delores Martes Jackson, who had divorced from Tito Jackson in 1993, drowned in a swimming pool, but the case was reopened, and her sons in 1995 filed a wrongful-death lawsuit against a man they accused of killing her. Three years later, the man was convicted of second-degree murder and sentenced to 15 years to life in prison.
If the jury concludes AEG Live has liability in Jackson's death, then they must put a dollar figure on damages -- including the emotional toll on the children caused by the loss of their father.
The oldest child, 16-year-old Prince, testified Wednesday that sister Paris, 15, "was probably hit the hardest because she was my dad's princess."
Paris has been hospitalized since a suicide attempt earlier this month, although it is unclear whether jurors will know about it.
"The loss of my uncle has hit her at a different level and she's in a tough spot, but we're loving her and doing everything we can," T.J. Jackson testified Thursday
He said he was at a loss for words to describe what Paris is going through. "It's tough, you know, it's tough."
"She was daddy's girl," he said. "My uncle was her world. My uncle gave them more love and for it to be taken away, it's been very hard for Paris, and for all of them."
Blanket, who was 7 when his father died, "was always wrapped around his leg, very shy," T.J. Jackson said. "Wherever my uncle was, Blanket was a foot away, My uncle was everything to Blanket."
"Right now, I don't know if Blanket realizes what he lost," Prince said. "He was so young. He is still growing up just like I am and he doesn't have a father to guide him."
Prince said he has "a hard time sleeping" since his father's death in 2009. It left him "emotionally distant from a lot of people" for a while, he said.
He's missed sharing with his father "the first day of going to school, having the first girlfriend, being able to drive," Prince testified.
T.J. Jackson said Prince was Michael Jackson's "little assistant."
"He was very mature for his age, very smart. My uncle would prepare him for things" by telling him about his business deals.
"He's very strong, he's very smart," he testified. "He was always the smartest kid I'd ever known."
As a guardian, T.J. Jackson said he must constantly deal with paparazzi stalking the children for photographs.
"It's, just to be frank, a complete annoyance," he said. "It's awful."
He suggested there should be a new law to protect celebrity children from photographers.
"I know it's making everything harder for the kids to grieve and to recover and to progress," he said.