You should make a report to your local authorities. It’s their job to make the determination if this is something to be concerned about or not.
Ummmm.....NO...not just NO but HELL NO it's the congregation's job to make the determination if this is something to be concerned about or not! Then, hopefully, law enforcement will agree and keep an on top of the situation.
Law enforcement is under ABSOLUTELY NO OBLIGATION to protect any one individual from crime but to catch those who perpetrate the crimes. It is up to us, individually, to keep ourselves safe.