The crime "shocks us deeply and brings back traumatic memories," Germany's Turkish-Islamic Union DITIB said in a statement on Wednesday.

"Again Solingen, another a fatal house fire, again late at night, again fire accelerators," the group added in a reference to an infamous arson attack in Solingen in 1993, in which five people lost their lives.

The 1993 attack, which later turned out had ben carried out by four young neo-Nazis, was one of the worst race-related crimes in Germany's post-war history.

'Xenophobic motive' not yet established

Tayfun Keltek, the head of the State Integration Council, said the current "heated atmosphere" made him assume that the latest incident was also driven by hate. "Unfortunately, we must assume that racist motives were behind the cowardly attack," Keltek said.

The young family who had lived in the attic apartment in the Solingen building included a three-year-old and a five-month-old child. The bodies of the parents – both in their twenties – and the older child were discovered first. Later the toddler was also confirmed dead. More than 20 other people were injured in the blaze.

An investigator reportedly found evidence of a fire accelerant in the wooden stairwell of the building, leading authorities to conclude that it was a deliberate crime.

Also read: Solingen house fire was arson, prosecutors say

However, the local public prosecutor and police said Wednesday that they had no evidence yet of a "xenophobic motive."

That angered DITIB, which claimed that everyone living the building except one person was a Muslim of Turkish heritage from either Bulgaria or Turkey. The victims of Sunday's attack were all Muslims with Bulgarian citizenship, according to the group.

An investigation into the attack is continuing, and police in Wuppertal on Thursday were calling for witnesses to phone the number 0202/284-1122 if they had any leads.

Four men charged over racist attack in Saxony

Meanwhile, eight months after an attack on a building housing refugees in the eastern state of Saxony, police said Wednesday that four locals aged between 20 and 22 years of age had been charged over the incident.

Authorities say that on July 23, 2023, two young men wearing balaclavas broke into the building and attacked two Afghans, aged 16 and 18 -- with a hammer and a metal pipe, among other things. They also were heard shouting racist slogans, according to a report by the broadcaster MDR Saxony.

Crimes against refugees and asylum seekers in Germany are on the rise, according to official statistics. Last year saw the highest number of such crimes since 2016, with 2,378 attacks on refugees themselves or on their accommodation.

With dpa