Two school custodians were found shot dead on Monday inside Mark Twain Elementary School in Chicago, in what police believe was a murder-suicide. Investigators say one of the custodians allegedly shot and killed his colleague before turning the gun on himself, though further details of the incident had not yet been confirmed.

The shooting took place within the school building, though it is unclear from initial reports whether it occurred during school hours or when pupils were present. Chicago police were continuing to investigate the circumstances surrounding the deaths, and no further information on a motive or the relationship between the two victims had been released at the time of reporting.