Ahlem D., a German-Tunisian student, was travelling back from a wedding with four relatives on Saturday night when the car she was in was shot at near the city of Kasserine in central Tunisia. The 21-year-old was killed along with her 18-year-old cousin.
Tunisian police claimed that they had signalled for the car to stop as they approached a road block, but the vehicle continued to advance at a high speed.
Ashraf Hendiri, Ahlem's cousin, told an AFP correspondent that he was also in the car and that the driver refused to stop fearing the people by the road were “terrorists”.
After not reacting to warning shots, the security officers opened fire on the car, Tunisia authorities said.
But Ahlem's aunt, Aziza D., is outraged at the police's version of events and described the killing as an "execution", the Kölner Stadt-Anzeiger reported.
"Her death is bad enough but how she died is worse," Aziza told the newspaper.
Aziza said that the three survivors of the five people in the car, including Ahlem's younger sister, had specifically driven on a rural road because they were afraid of the police.
She does not understand the police claim that the family car was driving too fast since "on those country roads one can't even drive fast.”
Two plain clothed policemen, without warning, opened fire on the car shooting Ahlem, her cousin Ons and a third relative, the aunt claimed.
Then "their mobile phones and purses were taken and they were beaten" before the policemen fled the scene. "We want justice for the dead," Aziza said.
The two women's funeral was held on Sunday in Kasserine.
Aziza has posted photos on Facebook of a smiley Ahlem but also images of the angry crowds that gathered outside the court in Kasserine.
The circumstances are still vague and the German Embassy in Tunisia is pushing for a clearer explanation.
"The foreign ministry must unfortunately confirm that a German national was fatally injured in Kasserine in Tunisia," a ministry spokeswoman told AFP.
"The German embassy in Tunis is in contact with the relatives as well as the appropriate authorities and is seeking swift clarification," she added.