Family says Michael Jackson's mother missing

(CBS News) Family members are concerned about the whereabouts and well-being of Katherine Jackson, the mother of Michael Jackson.

An attorney for Katherine Jackson said in a statement to CBS News that her grandchildren are concerned about her health after she was out of communication with them since last Monday.

Michael Jackson's daughter Paris has also expressed her concern on Twitter, pleading for information on her safety.

Lawyer Sandra Ribera said Michael Jackson's children, of whom Katherine is guardian, last saw their grandmother on July 15, when she was "in great health physically as well as mentally."

Ribera said that last weekend Katherine Jackson was preparing for a road trip to attend her sons' Unity Tour, in New Mexico, Arizona, and Las Vegas, when a doctor visited her home and ordered her to fly rather than drive.

Ribera said that Katherine Jackson ultimately did not attend the concerts, and that her longtime physician confirmed that his office did not send the doctor to her home last weekend.

"It has further been discovered that the doctor that Katherine Jackson last saw has been publicly reprimanded by the California Medical Board for fraudulent activities and has ties to Dr. Conrad Murray," Ribera said.

"Knowing that their grandmother has never gone more than 24 hours without checking in with them when she travels, her grandchildren grew concerned after they failed to hear from her and contacted family members asking to speak to her. Michael's children were told by family members who were allegedly with Katherine Jackson that their grandmother was not available to speak to them. . . .

"Concerned family members, particularly Michael's children, have since made ongoing pleas to those believed to have knowledge of her location for information regarding her whereabouts. The only reports provided have been both conflicting and confusing - especially those pertaining to [her] health."

Early Sunday Paris Jackson tweeted the following messages:

"yes, my grandmother is missing. i haven't spoken with her in a week i want her home now."

"if anybody sees my grandmother, please call the authorities or this number -- (818)-876-0186 it's the security number .. thank you so much"

"the same doctor that testified on behalf of dr murray saying my father was a drug addict (a lie) is caring for my grandmother... just saying"

A report was filed on Saturday with the Sheriff's Department.