Pop star Kesha's mother has filed a countersuit against top producer Dr. Luke for tormenting her by allegedly sexually assaulting her daughter.

In new legal documents, obtained by Tmz.com, Pebe Sebert claims the hitmaker, real name Lukasz Gottwald, raped Kesha in a way "as not to be tolerated in a civilized society". She claims she now suffers emotional distress and post-traumatic stress disorder as a result of his actions.

Her filing is the latest drama in the Kesha/Dr. Luke saga, which began when the Tik Tok singer filed a sexual abuse lawsuit against her one-time mentor in October (14). She accused him of subjecting her to years of sexual, physical, verbal and emotional abuse after he signed her at the age of 18, claiming his actions led to her 60-day stint in the Timberline Knolls rehab clinic in Illinois earlier this year (14).

Gottwald promptly filed a countersuit, claiming all the allegations were false and that Kesha was trying to extort him to break free from her contract.

He also hit Sebert with a lawsuit at the end of October (14), alleging she lied about the pop star's sexual assault claims against him in a bid to break their contract. He insisted mother and daughter had been threatening to go public with various stories about his alleged inappropriate behaviour unless he released the singer from her management contract.

He asked for at least $75,000 (£46,875) in compensatory damages as well as punitive damages.

Gottwald also noted that Kesha stated in a 2011 deposition linked to another case that he never made any sexual advances towards her.

But now her mother claims Dr. Luke gave the singer a date rape drug and raped her. She alleges her blood pressure has spiked as a result of the drama, and she had to be medicated during a recent therapy session when she become hysterical while discussing her daughter's relationship with the producer.