SA Supreme Court rules Cynthia Ellen Rigney was not ‘mentally incompetent’ during Maria Luis killing

A court has made a key ruling in the case of a woman who stabbed a drug dealer 34 times while allegedly hunting for a $50 bag of cannabis.

The young woman who stabbed a drug dealer 34 times allegedly over a $50 bag of marijuana will stand trial for murder after a Supreme Court justice ruled that she was mentally competent at the time of the frenzied attack.

Cynthia Ellen Rigney stabbed cannabis dealer Maria Luis 34 times within three minutes in the Adelaide suburb of Kilburn on December 7, 2018.

Police raided Ms Rigney’s unit at 10.51pm that night, finding her asleep under a blanket in her bedroom with a plastic resealable bag containing marijuana attached to her leg and arrested and charged her with Ms Luis’ murder.

A search of the premises uncovered knives secreted in the bedroom and lounge room as well as a black handbag spattered with a bloodlike stain, which DNA analysis connected to the 61-year-old dealer.

Ms Rigney, now 25, has pleaded not guilty to the charge of murder.

Her defence team and prosecution have agreed to the “objective facts” of the case, that Ms Rigney stabbed Ms Luis, but the long-running trial has turned on whether the young woman was mentally incompetent at the time of the alleged murder and whether she was fit to stand trial.

Cynthia Ellen Rigney (left) was arrested and charged with murder in 2018. Picture: 7News

Ms Rigney has treatment-resistant schizophrenia and she claims not to have remembered stabbing Ms Luis.

Expert witnesses provided reports on Ms Rigney’s complex swirl of mental health problems, which together offer a conflicted picture of the young woman’s capacities.

In one instance, a psychologist concluded it was hard to say whether Ms Rigney’s inability to recall events on the day of the stabbing was a consequence of psychosis or whether Ms Rigney had feigned memory loss.

Some experts also altered their opinions on Ms Rigney’s mental competence as more information came to them.

On Friday, Justice Anne Bampton ruled that it had not been established “on the balance of probabilities that at the time of the stabbing, Ms Rigney did not know that her conduct was wrong; that is, that she was completely incapable of reasoning about whether the conduct, as perceived by reasonable people, was wrong”.

Justice Bampton’s detailed 112-page judgment also concluded that it had not been established that “she was totally unable to control her conduct”.

Ms Rigney was 18 at the time of the alleged murder. Picture: Supplied.

“I am not satisfied it has been established, on the balance of probabilities, that Ms Rigney was, at the time of the stabbing, mentally incompetent to commit the offence of murder,” she said.

Justice Bampton ruled “there was no evidence either from Ms Rigney herself or any other source proximate to or at the time of the stabbing that Ms Rigney’s actions were guided or directed by psychotic phenomenology”.

“There is no evidence before me that the stabbing was the result of florid psychosis or a delusional belief arising from her treatment-resistant schizophrenia,” she said.

“However, there is evidence of a credible, non-psychotic alternative explanation for the stabbing.”

Justice Bampton also said the “frenzied nature” of the stabbing or number of stab wounds did not point to either a psychotic or non-psychotic motive for the young woman’s conduct.

The judge-only trial now continues and Ms Rigney will next appear for a directions hearing on August 18.