Montgomery County, Maryland, officials said a young woman kayaking along the Potomac River died on Sunday after she was trapped in the water.

Montgomery County Fire and Rescue spokesperson Pete Piringer said officials responded to a call for assistance at roughly 3:15 p.m. in the area of the C & O Canal National Historic Park.

One adult female, Piringer said, was pinned “under a rock (in hydraulics)” when multiple people came to try and help her. The woman is believed to be one of roughly two dozen adults traveling to the area with an out-of-state college kayak group.

Details on how the woman became trapped remain under investigation by officials.

Hours after first responders arrived, despite aid from passersby and support from first responders, the unidentified woman died.

Piringer said that D.C. police are currently investigating the incident.