Police said on April 1 that six people were killed in a fire in a packed nightclub in the northern Serbian city of Novi Sad overnight.
Police said the fire appeared to have started in the stage area of the “Contrast” nightclub during a live performance shortly after midnight.
Some 300-350 people are believed to have been in the club at the time.
Investigative judge Ana Stamenic said 50 people had been taken in by police for questioning, including the owner of the club.
In 2008, eight people died in a fire in the Lounge cafe in Novi Sad and three died in a fire at the city's Putnik hotel the previous year.
Based on reporting by AP and Reuters