Three Indian nationals were killed in a fire at a residential building in the German city of Bochum, local media reported on Wednesday.
The victims were two women aged 25 and 27, and a 26-year-old man, all Indian nationals, German public broadcaster WDR (Westdeutscher Rundfunk) reported, citing details released by Bochum police.
Their names and home states in India were not reported.
Five other people were also injured in the incident that occurred early Tuesday. Their nationalities and other details were not specified in the media reports.
Police have arrested a 41-year-old resident of the building on suspicion of murder. He is a Romanian national, German news channel n-tv reported, citing the German Press Agency Deutsche Presse-Agentur (DPA).
A Bochum police spokesperson told WDR that there were initial grounds for suspicion of murder against the man, who had been questioned by officers from the homicide squad.
Police and prosecutors announced the arrest on Wednesday.
Investigators have ruled out a technical defect as the cause of the fire and suspect arson, but whether the fire was deliberately set or started accidentally remains under investigation.
The fire broke out early on Tuesday in a multi-family residential building in Bochum's Hofstede district. Emergency services were alerted around 4.15 am local time.
Firefighters found the three victims dead in an apartment on the second floor. The five injured people suffered smoke inhalation and were taken to hospitals in Bochum.
The firefighting operation was particularly difficult because the flames had spread upwards through the stairwell, preventing firefighters from using it to reach residents on the upper floors, WDR reported.
Firefighters rescued two people using a turntable ladder, two using portable ladders and another person with a safety cushion, according to the DPA report carried by n-tv.