Early last week, we reported that Courtney Love lost custody of daughter Frances Bean Cobain, her only child with her late husband, rocker Kurt Cobain.

What wasn't specified was why Frances Bean is now under guardianship of Kurt's mother and sister (sparking a series of Facebook rants from Courtney).

A new clue has just surfaced, however. Lawyers in the case have asked to seal the documents relating "to a minor and allegations of domestic violence."

Documents were filed by lawyers December 11 for the Cobains' guardianship, which was established on behalf of minor Frances Bean Cobain, who is 17.

Courtney Love and Frances Bean Cobain in pre-restraining order times.

A judge stripped Love of legal control over her daughter. Court papers do not get specific, either, but do refer to sealing Frances Bean's medical records.

The docs also say, "In this proceeding, every document reveals details of Frances's (sic) relationship with her mother." It sounds like abuse was alleged.

A restraining order now prohibits "Courtney Love Cobain from certain behavior and from coming within a certain distance of Frances and her guardians."

Love's online ramblings - most recently warning her daughter not to become Jamie Lynn Spears - are well documented, but her attorney says she has not relapsed and this "is simply about Frances preferring to live with her grandmother."

We'll see if more information becomes available and whether that's true.