Police first discovered a blood-covered body in August last year in a parked Mercedes in southern Germany, but the true identity of the body raised questions, leading to an investigation that has unveiled a possible motive for the killing.

Authorities say Sharaban K, a 23-year-old beautician of Iraqi descent from Munich, searched for women who resembled her closely online before killing one of them in order to go into hiding, German news outlets are reporting.

The case has been dubbed the "doppelganger murder", in reference to a German folktale about a ghostly identical spirit, but the word doppelganger also has come to mean a stranger who looks like a twin.

The suspect and others involved in the case are being referred to by their first names and last initials, as is customary in the German legal system.

Police first discovered a blood-covered body in August last year in a parked Mercedes in Ingolstadt, southern Germany.

Reports initially identified the victim as Sharaban K, but a post mortem examination raised questions about the body's identity.

The victim was eventually named as Khadidja O, a 23-year-old beauty blogger from the neighbouring state of Baden-Wurttemberg.

Police later stated the victim and Sharaban K were "strikingly alike" in appearance due to their physical similarities such as straight black hair.

On 19 August, officers detained Sharaban K and a friend accused of plotting the scheme.

The full extent of the case and their alleged motives were not publicly disclosed by authorities until this week, and it is has now emerged prosecutors believe Sharaban K planned to fake her own death due to a dispute with family.

"Investigations have led us to assume that the accused wanted to go into hiding because of a family dispute and fake her own death to that effect," Veronika Grieser, of the Ingolstadt state prosecutor's office, said in a statement.

Ms Grieser explained that investigations uncovered several attempts by Sharaban K to reach out to women on social media she resembled in the week before the alleged murder.

She is said to have operated under aliases and attempted to set up meetings with the women.

While many of these attempts proved unsuccessful, she eventually managed to set up a meeting with Khadidja O by making a "cosmetics offer", authorities allege.

Sharaban K and Sheqir K are accused of picking up the woman before taking her to a forested area between Heilbronn and Ingolstadt, before stabbing her to death.

Arrest warrants were issued for both women last week, and they each face life in prison if convicted.

Police spokesperson Andreas Aichele told the German tabloid newspaper Bild: "The crime weapon has not been found, but the evidence is overwhelming. The victim was killed with over 50 thrusts of the knife, the face completely disfigured."