Police say people know who shot the 12-year-old girl to death in Botkyrka on Sunday night. But getting these people to step forward is far from the easiest.

As a result, the question of whether anonymous testimonies should be allowed in Sweden has been brought up again.

Sven-Erik Alhem, former chief prosecutor, thinks it could be a good complement to anonymous witnesses.

- There is absolutely no solution to the problem. But you can increase the attack possibilities in certain extreme situations where you would not otherwise come forward, he says in Morgonstudion.

"The defense gets a huge uphill"

Dennis Martinsson, PhD in criminal law, does not really agree.

- If you allow anonymous witnesses, you do not know if it testifies because it actually wants to. Or is there a background story between the witness and the accused. This gives the defense a huge uphill climb, he says.