Combine 3 pieces of evidence which will clearly point to the time the fire occurred

By combining the information from the photograph with Joseph Bremer, the burned clock  and the police report we can conclude that fire occurred around 11:50 p.m

Check GPS tracking and location of driver at the time of fire

The location of the house is present on another map

If you combine 2 maps you will see that Carl only reached the location at 00:04, which is after the fire had occurred. He has an alibi

Carefully analyze the list of the club members and their relation to two of our suspects

There is a connection between the club members and the article in the newspaper

The Fischer Brothers (members of the fan club) were arrested in the Stadium and must serve a 15day sentence starting from May 24th, therefore they could not be present at the location of the fire

Check the web site listed on the matches

Check the time of the photos taken in the Adlers king club by Lukas, his friends and the Club itself.

Match the time of the photos with the duration needed (shown on the map) to reach the house from the club

On their personal Facebook pages you can find selfies, which were taken at 11:40pm and 12:00am, time required to reach the house is 6 min. Plus time for the arson. Lukas would not be able to make it in such a short time

The filled out treatment plan will look like the following:

Check the complaint from Walter Sievers

According to the treatment plan, it could be seen that Walter Sievers was given a strong tranquilizer on May 30that exactly 23:00. Matching it with his complaint that he sleeps at least 2 hours after it you can see that he could not make an arson

From the letter you can see that Alma Preuss had an affair with Joseph, she sent proof (jetton). Where was this letter was sent from?

Check the newspaper to know what happened on Mallorca at the same time

On Palma de Mallorca all flights were cancelled  between  May 29th and June 1st. Same as the rock band, Alma could not leave the island because of the storm and therefore did not commit the arson.

it das Feuer nicht legen.

Closely check the registration of the visitors in hotel

Closely check the visual look of the visitors entering the hotel room

Registration of number 8 is fake, as visitors registered with the names of characters from Harry Potter (registration 8)

The lady in the picture is dressed similar to the kids drawing

The man on the picture is dressed similar to the man filling the fuel at the fuel station

It seems that Joseph’s driver has an affair with Joseph’s wife, but at the time of arson there were together in the hotel room.

Check the notebook with the encryption page

After decrypting the message, you will get that Joseph cancelled his trip with Alma as he had his wedding day on May24th

The wedding day is the key

Check the link in the notebook to website and use key 2405

The insurance documents in the website clearly indicate that Bremer was insured against fire and could claim the insurance benefits in such case.

Look closely to the medical report(s) one or more reports?

His medical report(s) also indicate that he was suffering from an iron deficiency anemia. He did not know that, as the analysis result did not arrive until after his death. An anemia patient can lose consciousness in case of an insufficient oxygen concentration in the air. All this indicates that Joseph, being sensitive to the oxygen concentration, fainted during the fire, remained unconscious and died.

All the characters of this story had different motives for this crime, but only Joseph had no alibi and apparently tried to set his own house on fire to claim the insurance money so he could pay his debts, but underestimated the severity of his illness, lost conscious and subsequently died in the fire.

So, the fire victim is the arson criminal.