ROME (AP) — Italian prosecutors say eight people are under investigation so far in connection to a stampede at a packed nightclub that killed six people, five of them teenagers.

Authorities stressed on Monday that the investigation of the stampede early Saturday was just beginning. They said they want to know about the security measures and capacity of the Blue Lantern disco in the small town of Corinaldo, as well as the panic that sent concertgoers running for the exits.

One hypothesis is that would-be thieves used irritant sprays on the crowd to hide thefts, which has been done at other concerts and gatherings in Italy.

The seven adults under investigation include the club owners and concert organizers. Prosecutors say a 17-year-old was added to the list because three witnesses "generically" identified him.