Parents are raising serous concerns after two underage girls wanted for armed robbery boarded a Rio Grande High Shool bus in Albuquerque’s South Valley and entered the campus, resulting in a lockdown, reported KOAT 7 .

The incident occurred May 15, when the unidentified girls managed to board the school bus, entered the high school campus, and hid in a second-floor bathroom stall before being discovered by staff and escorted out.

According to the news report, the girls fled on foot but were quickly apprehended by Bernalillo County Sheriff’s deputies, who confirmed that both girls had outstanding warrants for armed robbery and were facing additional charges from Albuquerque Public Schools (APS) police.

A letter sent to parents explained the timeline of events and how students had reported seeing to “suspicious females” on campus. This report prompted staff to initiate a “shelter in place” protocol, securing classrooms while searching the building.

Parents told local news reporters that they wondered how the girls managed to get on the school undetected. APS told reporters that the incident should not have happened. Additionally, the school districtc stated that school bus drivers are required to contact dispatch via radio when hey encounter an unfamiliar student, to verify the child’s name, address, school and other relevant details. It is unclear if the driver of the bus involved in the incident is facing any consequences for not following protocol.

The Bernalillo County Sheriff’s Office said suspects are expected to face new charges in addition to their other warrants. As questions are left unanswered, parents demand more transparency from APS and its transportation providers.

The case remains under investigation.