SAN DIEGO (KSWB) – A mountain biker died Saturday while trying to save four hikers who were found suffering from dehydration in Southern California, Cal Fire confirmed.

A call came in around 2:45 p.m. reporting at least seven people in heat distress at Carrizo Gorge in San Diego County’s Jacumba Mountains, officials said. Cal Fire ground crews and a sheriff’s helicopter were called to assist.

Upon arrival, Cal Fire says there were four hikers at least five miles away from the trailhead. The hikers had been rescued with the assistance of four mountain bikers who happened to be in the area.

Two of those mountain bikers were at the bottom of the hill when emergency crews arrived, while the other two remained with the hikers. The temperature around the time crews arrived was reportedly about 106 degrees.

The sheriff’s helicopter was used to transport the hikers from the trail. They were evaluated by paramedics and all refused transport to a hospital, Cal Fire explained.

After the rescue, the two mountain bikers that remained with the hikers started riding down the trail, but they reported getting separated from each other. A short time later, the mountain biker was found unconscious at the quarter marker past the trailhead.

The individual was carried out and placed into an air-conditioned vehicle until an air ambulance arrived, according to Cal Fire.

Sometime between transportation to the hospital, officials say medics began performing CPR on the distressed mountain biker, who was then pronounced deceased.

The gender, age, and identity of the victim have not been released. The exact cause of death will be determined by the San Diego County Medical Examiner’s Office.

In a Facebook post after the incident, Cal Fire stated:

“A huge thank you to the bystanders that were able to lead the firefighters and rescue helicopter in to where the patients were in this very rugged and remote area. Please remember to bring an adequate amount of water and food if you are enjoying our backcountry and try to plan activities earlier in the day when the temperatures are cooler. Also, hike in a group and let friends and family know where you’ll be and what time you expect to finish.”

FOX 5’s Danielle Dawson contributed to this report.