Three Nazis were later convicted for the bombing. Photo: Tomas Oneborg/TT as well as the Police.

Relevant to this article is the article "The court was not allowed to see important evidence at Nazi trial" from the next day.

[Public service radio news] Ekot can today reveal that Nazis in the beginning of 2017 were able to place a bomb at a refugee housing in Gothenburg in spite of [Swedish Security Service] SÄPO having them under surveillance. One of the Nazis was a suspect for a previous bombing.

– We saw electronics there, among other things a black tube that looked like a battery of some kind. It actually started ticking too, like an egg timer. Then it hit us that it could be a bomb, tells the location manager at Lilleby camping, Tommy Lassinati.

It is January 25, 2017 and he looks in a ICA [retail chain] bag that is standing behind one of the camper homes at the camping. The ICA bag contained a bomb on a timer.
– One of the cords had come loose from the egg timer.

So if it had not been disconnected when the egg timer finished ticking it had exploded?
– Yes absolutely, it would have.

Three Nazis were prosecuted and are later convicted for the bombing. But when we review the preliminary investigation protocols it becomes apparent that the Security Service had several opportunities to stop the bombing.

Already in the middle of December the Security Service got to know that the local Nazi leader Viktor Melin’s DNA was found on a bomb that had exploded outside premises in central Gothenburg, being used by leftist activists.

Public Prosecutor Mats Ljungqvist at the Public Prosecution Office for Security Cases becomes the preliminary investigation leader. In spite of the DNA hit he decides to not arrest Viktor Melin.
– Physical surveillance is placed on him to unravel how he moves, and who he contacts.

But the decision to not arrest Viktor Melin at once shows to have serious consequences. At the same time as he is under surveillance by SÄPO he and a buddy obtains materials that they use to build a new bomb. At one of the events SÄPO’s surveillance agents are even present too in the store. The surveillance agent tells it like this in the District Court
– When I enter, Melin is standing quite close to the right and looks at items that belong to housing or hobby. They talked very quietly with each other, as if because nobody else should hear. I walked around to hear what they said, and then they went quiet.

With SÄPO’s surveillance agent on his heels Viktor Melin buys plastic boxes, superglue, nails, and if one is to believe the preliminary investigation then travels to buy egg timers that may be used to make a bomb on timed delay.

Viktor Melin  also obtains dynamite. Probably the delivery occurs on a parking where he meets another, explosives knowledgeable, Nazi, Jimmy Jonasson. SÄPO’s surveillance agent tells in the District Court:
– They have squeezed in with the rear end farthest in against the parking lot square, so it is impossible to see inside. I reacted against it being a cumbersome parking. We believe they did something, but we can not say what they did.

The man that they meet at the parking, Jimmy Jonasson, works as a construction diver, and it will turn out he has an entire container filled with dynamite on his yard a bit from Gothenburg. But that it would be dynamite that was handed over the Public Prosecutor Mats Ljungqvist only understands later.
– It is described as a conspiratorial meeting. I do not remember the wording, but I made the interpretation that something could have been handed over at this event.

At the evening of New Year’s Eve the surveillance agent of SÄPO follows Viktor Melin when he and another organized Nazi travels to Lilleby camping, which was used as a refugee housing.
– I sit in the car located closest to the vehicle in question. And when they go onto the deserted road which later leads to Lilleby camping I choose to turn off, the surveillance agent tells to the court.

The two Nazis park and sneak through the forest towards the camping. Preliminary investigation leader Public Prosecutor Mats Ljungqvist is off duty but gets a phone call from a colleague that is on call.
– SÄPO is nervous over that two persons with ties to the Nordic Resistance Movement [NMR] are located there, especially as there is information that NMR has had a special campaign aimed in particular against Lilleby camping. This altogether gives a rather worrisome picture.

But he does not see any cause to arrest the two Nazis or alert the refugee housing.
– At that time we do not primarily suspect that a bomb has been placed. Rather there are other hypotheses as to why he is moving in that area. And if we had seen any signs that it was a matter of a planned bombing spree we had naturally done something about it. I presume that, that we had ended it, says Public Prosecutor Mats Ljungqvist.

– I do not understand why this was not ended, says Magnus Ranstorp, one of Sweden’s premier terror-researchers.
– It is very remarkable. There are major reasons for them to know that it can develop to become dangerous.

It is New Year’s night, it is dark, they park right next to the forest, they have previously placed a bomb and they walk a sneak route up towards the camping. How would you interpret the situation?
– I would interpret it as something is about to happen, due to the locality, due to who was there. There is a history and there is no reason to take this any farther, and that it can come to endanger the life of another.
– I believe that every person that hears this would pose serious questions as to why this was not ended because it could have gotten really, really serious.

Neither is the camping searched for any bomb. Only over three weeks later the bomb is found by the location manager at the camping.

Why is the camping not searched?
– I can not answer that. The Security Service get to answer that. I have no reason to give their decision a review, says preliminary investigation leader Mats Ljungqvist.
– Should one have searched the camping? Yes with the results in hand one should have done that.

The three Nazis are convicted for the bombing at Lilleby camping. Viktor Melin is also convicted for the fist bomb, at the Syndicalists’ premises. Melin and Jonasson are later prosecuted also for a third bombing against a refugee housing, where a cleaner is seriously injured. This too is to have happened after SÄPO started surveillance on Melin. Viktor Melin can not be tied to the bombing location and both are acquitted by the Court of Appeals.

We have sought the Security Service but they have chosen not to participate. We have also sought Viktor Melin and Jimmy Jonasson, but without result.

This is a translation of the original public service radio article, as it was published on 2018-03-07, 04:00 local time.
The translation was done, due to global relevance and lack of official translation, by @b9AcE to the best of my ability.

Update.
A later article (as published 14:40 local time) also by public service radio contains the following audio segment, translated by me below, with the following title:

The sharp demand: Investigate [the Swedish Security Service]

The Parliamentary Ombudsmen [JO] must investigate if the prosecutor and SÄPO [Swedish Security Service] acted correctly when when they did not intervene in spite of seeing the suspected people they had under surveillance bought materials for a bomb,
That is the opinion of Sven-Erik Alhem, former Director of Public Prosecution Authority.
The suspected people also traveled to a refugee housing where SÄPO’s surveillance agent thought to see them make a weapon ready to fire, without them intervening.
Alhem: I would myself, if I myself was JO, I would definitely make a decision ex officio to begin an investigation regarding this.
Reporter: To get an answer to that question, if this was right or wrong.
Alhem: Yes, to get a complete investigation that can be the foundation for an assessment, simply. It is almost so that I have called on JO to make a decision.
Reporter: Yes, that is what you are doing now.
Alhem: Yes… but it is not certain that JO thinks the way I do.

Reporter: To not act against a person that is in the act of committing a crime, or is about to commit a crime, but instead defer and wait until one can prove even more serious criminality, that is called interimistic passivity.
That is a difficult judgement call according to Sven-Erik Alhem, to know when one should act and when one should not act and according to him there are no easy answers.

Alhem: It can be a difficult judgement call, to choose when one should act. If one acts too soon, then one risks to lose everything and forewarn those that one is performing survelliance against, that one is on their heels.
Reporter: Because in that which you have taken part of, can you see something right or wrong there?
Alhem: No that is, I don’t want to in a haphazard manner say anything, it would be wrong of me to make a call in the case, but… I reacted on what I heard being reported in the story and thought it was strange.