Three children and a teenage girl died in a suspicious fire which engulfed a four-storey residential building in the Saudi city of Jazan.
Civil defence personnel rescued eight other people from the fire which broke out first in a flat on the fourth floor, according to Sabq newspaper.
The four victims were reportedly found naked, strangled to death and handcuffed which led the Public Prosecution to launch a criminal investigation.
The building, which was previously used as a hotel, has been transformed into a residential building, said Jazan Civil Defence official spokesperson Lieutenant-Colonel Yahya Al Qahtani.
The mother, who is said to have psychological problems, refused to open the door, which led the firemen to break it and rescue those who were still alive.