The man’s attorney said that he denied all charges against him.
Prosecutor Helena Treiberg Claeson told the TT news agency that the man’s arrest on Friday was “expected” but that “it is still very early in the investigation”.
The woman, who was the 33-year-old partner of the suspect, and the couple's three children, aged two to eight, were found dead in their apartment on Thursday after neighbors reported a fire in the residence.
However, investigators believe that the fire was likely an attempt to hide the father’s alleged actions. All four victims were found with “injuries to their bodies that are unrelated to the fire,” police press spokesperson Thomas Fuxborg told TT on Thursday morning.
Swedish media outlets including Aftonbladet and Expressen have reported that all four victims had their throats cut, but police had not confirmed that as of Saturday. Aftonbladet also reported that the suspect is a Bosnian citizen.
Autopsies will be conducted next week, Claeson said.
The man's defense lawyer, Poly Jensell, told TT that her client completely rejects the allegations.
“He says he was not there when the fire started, but he was in the vicinity of the residence when he was arrested. The reason was that he had been called about the fire and was urged to get home quickly,” Jensell said.
“He is dealing with immense sorrow, as he has lost most of his family and is also accused of an extremely serious crime,” she added.
On the same day that the family was found dead, they were due to be evicted from their home in the Angered district of Gothenburg, according to Aftonbladet. The family had large debts and their rent had not been paid for two years.
The leasing manager of the family’s apartment complex said that social services had been involved.
“I think it is horrible. I have no words, I can’t comprehend it. It’s so tragic,” Anna-Carin Lundblad, the leasing manager, told Aftonbladet.