A girl cries as lifeless bodies lie on the ground outside disco Lanterna Azzurra in Corinaldo, central Italy, Saturday, Dec. 8, 2018. A stampede at a rap concert in an overcrowded disco in central Italy killed five young teenagers and a woman who had accompanied her daughter to the event early Saturday, police said, adding that 59 people were injured. (AP Photo/Bobo Antic)

Rome - Eight people have been placed under investigation in connection with a weekend stampede at an Italian nightclub in which six people died, prosecutors said Monday.

An underage boy is suspected of involuntary manslaughter and causing bodily harm, youth crime court prosecutor Giovanna Leboroni said in a press conference in Ancona, as quoted by ANSA news agency.

However, the strength of the evidence against the suspect "has all yet to be seen," Leboroni added, sounding very cautious about the development.

Another seven people - four owners of the nightclub venue and three businesspeople who ran it - are also being investigated, Ancona Chief Prosecutor Monica Garulli said in the same press conference.

Saturday, six people died in Corinaldo, near the Adriatic town of Ancona, following a stampede that is suspected to have been caused by someone using pepper spray inside a crowded nightclub.

People rushed outside and died after a parapet near the club gave way, resulting in people falling into a ditch and being crushed by others falling on them.

Crowds were waiting for a concert by Sfera Ebbasta, an Italian trap singer. Five teenagers aged 14-16 and a 39-year-old woman who was there with her pre-teen daughter were among the dead.