Coleen Lamarre, the mother of accused killer cop Beau Lamarre-Condon, beamed into Sydney's Downing Centre Local Court from a prison cell on Thursday.
The 63-year-old former police officer has been charged with perverting the course of justice but has not yet entered pleas.
She wore prison greens and took copious notes with pen and paper as her barrister applied for her to be released on bail.
The application was refused, meaning Lamarre will remain behind bars for two months if she doesn't make a bail application in the state's highest court.
She is accused of attempting to influence a witness in the trial of her son who, like her, previously served as a police officer.
Lamarre-Condon allegedly fatally fired his service pistol at TV presenter Jesse Baird and his flight attendant partner Luke Davies at their inner-city Sydney home in February 2024.
The former police officer bundled their bodies into surfboard bags and dumped them at a rural property in Bungonia near Goulburn, according to prosecutors.
The men's bodies were found eight days later after an extensive search.
Lamarre-Condon, who briefly dated Mr Baird, has pleaded not guilty to their murders.
He joined the force in 2019 and was the first serving NSW police officer charged with murder in decades.
The then-senior constable was charged and eventually sacked by NSW Police after handing himself in.
He faces two counts of domestic violence-related murder, and aggravated break and enter. His case will return to court later this month.
The proceedings have become one of the state's most high-profile criminal cases in recent years, with suggestions hundreds of witnesses may be called to testify at trial.
In a previous hearing, Lamarre-Condon said he opposed any orders for a closed court at his trial, adding he "will not be silenced".