The arrested man is suspected of probable cause, the higher degree of suspicion, for murder.

"He continues to deny crime," said prosecutor Kristoffer Sahlin.

At the same time, the suspicions against the three men who had previously been arrested but were released on Monday have weakened.

It was the night of Saturday when the seriously injured man was found in central Uppsala. His injuries were life-threatening and he died on Monday.

One of the police theories about the cause of the murder is that it is about a hook-up that has derailed.

- Two companies end up in some sort of quarrel inside the restaurant Terrace. At half-time at night, the trouble continues on Drottninggatan and then onto Trädgårdsgatan where one of the guys sustains a very serious injury, says Jonas Eronen, the police spokesperson.

After that, the knife-stricken man goes via Slottsgränd down to the Västgötaspången where he descends.

Seeking witnesses

Police are now looking for witnesses to the entire incident.

- If anyone has seen something that may be of interest to us, we want to hear from them, says Jonas Eronen.

Police investigators have seized some technical evidence that is being sent for analysis. At the same time, interrogations were held with people from both the societies that ended up in trouble on Saturday night.

What do you know about those involved?

- According to the information I have, they are not known by the police before, says Jonas Eronen.

By June 16, charges should be brought against the arrested man.