A 17-year-old girl became the fourth person to die from being crushed in a stampede at a Halloween rave party in Madrid after she succumbed to her injuries in hospital on Saturday, Spanish media reported. The girl had been in critical condition after the stampede at the Madrid Arena concert venue early on Thursday morning at which police said three young women died. 1 other young woman who was injured in the stampede remained in hospital in serious condition. The fourth victim, a girl of 17, died on Saturday morning, RNE national radio reported, citing hospital sources. Spokespeople at the Hospital Universitario 12 Octubre were not immediately available to confirm the reports. Police and witnesses said the stampede inside the concert hall, which had a capacity for 10,500 people, appeared to be sparked by someone throwing a flare. Several Spanish newspapers on Saturday reported claims that the arena had been overcrowded. A spokesman for the Diviertt company that organised the event, Jorge Morales, told Cadena Ser radio that 9,650 people entered the concert and there was \"rigorous control\" of people entering.