One of the men accused of killing psychology student Bianca Warburton told the Alexandra Magistrate's Court on Monday her murder was a "mistake".

"It was a mistake," 25-year-old Ntembiso Msalaku said, in an English translation of a statement given to the court.

He intended to plead guilty. He appeared alongside his co-accused Mpuhumazi Gumede, 29, and Moffat Mthoti, 27.

All three were dressed in T-shirts and jeans, and were brought to court in shackles.

Magistrate Renier Boshoff said they faced a very serious charge.

"This offence could lead up to a sentence of a minimum of 25 years."

It was not known how Gumede and Mthoti would plead.

Msalaku asked the court for legal aid while the other two accused said they would represent themselves.

All three were arrested on Saturday in connection with the murder of 24-year-old Warburton near the Alexandra clinic last Wednesday.

The intern had stopped her car at a stop street near the clinic when the trio, one of them armed, confronted her. They allegedly attempted to hijack the vehicle and then one of them shot her in the upper body.

She died on the scene. They ran away without taking anything.

No family members appeared in court.

The men would remain in custody until November 13, their next court appearance.

The postponement would also allow for further investigation.