So was a warrant issued or not? In the US, at least, being "unable to formally notify [someone] of allegations" would not prevent a warrant from being issued.
Top prosecutor Marianne Ny said his arrest warrant was being revoked as it was impossible to serve him notice.
https://www.bbc.co.uk/news/world-europe-39973864
You are unlikely to come to sound conclusions if you reason on the basis of your knowledge of US law. Sweden is not the US.
There are many differences between the US and EU/UK.