Senior Dresden public prosecutor Christian Avenarius said that a lawyer for the dead woman's husband had begun legal action six weeks ago.
Last week, Alex Wiens, 28, was sentenced to life imprisonment for stabbing to death Marwa El-Sherbini in a Dresden court room.
On July 1, Wiens plunged an 18-centimetre kitchen knife at least 16 times into Sherbini, 31 and three-months pregnant at the time. Her son, three-year-old Mustafa, watched her bleed to death at the scene. Sherbini had taken Wiens to court after he racially abused her in a children's playground.
Sherbini's husband, Egyptian geneticist Elwy Okaz, rushed to her aid but was also stabbed repeatedly and then shot in the leg by a guard who apparently mistook him for the attacker.
According to a Cairo newspaper report, Sherbini's family is accusing the judge who was presiding over the court, and the court's president, of failing to arrange proper security, thereby making them accessories to her death.
Despite knowledge of Wiens' “criminal intent” there had been no special security arranged, one of the family's lawyers said.
The family is also in discussion with the state of Saxony over compensation, the lawyer said.
Sherbini became known as the "veiled martyr" after her death provoked outrage in the Muslim world.