Two Chicago Public Schools custodians are dead after a shooting Monday afternoon inside Mark Twain Elementary School in the city's Garfield Ridge neighborhood, near Midway Airport. Chicago police say the shooting happened around 3:40 p.m. in the 5100 block of South Lotus Avenue, while the school was empty for summer break.

According to FOX 32 Chicago, the victims — a 48-year-old woman and a 63-year-old man — were both rushed to Christ Hospital in critical condition and later died. Both were longtime members of SEIU Local 73, the union representing Chicago Public Schools support staff.

Police believe the shooting was a murder-suicide carried out by a 20-year veteran custodian who had recently learned he was being relocated from Mark Twain to another school assignment, a decision investigators say left him upset in the days beforehand, per a police report cited by the Chicago Sun-Times. Authorities say he shot his coworker before turning the gun on himself inside the building.

Chicago Public Schools has not publicly identified the victims and said it is offering counseling resources to staff at the school and across the district. SEIU Local 73 said it is working to support the families of both members through the union's emergency assistance programs, according to WTTW News.

No students or other staff were in the building at the time, and police say there is no ongoing threat to the community. The Cook County Medical Examiner's office is expected to formally rule on the causes of death, and the shooting remains under investigation by the Chicago Police Department's Bureau of Detectives.