Just before 4 pm on Wednesday 15 June, the police received an alarm about a knife cutting on Söder in Helsingborg.
A man in his 20s was found to have life-threatening injuries.
The next day, a man of the same age who has now been arrested was arrested on suspicion of attempted murder.
It is unclear whether the detainee admits the crime or not.
But the investigation continues.
- With the help of all the evidence, we are creating an image of what happened, says Matthias Gustafsson, the police investigation leader.
The knife-cut man is still being cared for at Helsingborg Hospital for his injuries.