The child-welfare investigators have been seeking a sit-down with the kids ever since the self-styled King of Pop was busted Nov. 18 for allegedly molesting a 12-year-old cancer survivor at the ranch.
Social workers have paid about a half-dozen visits to Neverland, but each time no one has been home, insiders said.
Jackson has not been seen in public since Nov. 18, when he turned himself in to Santa Barbara County, Calif., authorities, posted $3 million bail and took a ride through Las Vegas.
L.A. defense lawyer Steve Cron (search) said he's not surprised authorities want to check up on the kids.
"You don't need to be convicted of anything to be investigated," said Cron, lawyer for comic Paula Poundstone, who lost her kids for a year due to child-endangerment charges.
Jackson has two sons, Prince Michael I and II, and a daughter, Paris. The Gloved One shocked fans a year ago when he dangled infant Prince Michael II over a German hotel balcony as he greeted fans.