By Trang Do

CHESTER, Pa. (CBS) — Concern grows in Delaware County as an 18-year-old man remains missing after authorities say he disappeared into Ridley Creek in Chester around 6:20 p.m. Saturday evening.

A relative told Eyewitness News the man was with a friend hanging out by the creek, when he had a seizure and fell into the water.

Multiple police, fire and EMS agencies launched an extensive search effort near Sun Drive and Hancock Street, close to the Eddystone border.

Along with search and rescue boats from Chester, Tinicum and Eddystone Fire, searchers used drones outfitted with infrared cameras, as they navigated north of the Chester Pike Bridge down to the Delaware River.

After about two-and-a-half hours, emergency responders called off the search until the morning due to the swift current in the creek from recent heavy rainfall.

Sunday, teams from Chester Police and Fire, along with medics from Crozer Chester Medical Center, returned to the creek with boats and Pennsylvania Wilderness Search and Rescue dogs, but once again came up empty.

Family members have also been helping with the search and say they’ve found the man’s hat and shoe, but nothing else. At this point, authorities are not saying if they suspect any foul play.

MORE ON CBSPHILLY.COM

Stimulus Package Update: Are Politicians Finally Ready To Make A Deal?

Pennsylvania Couple Charged With Severe Abuse Of Their 8 Children

Hershey’s Facing Social Media Backlash After Changing Popular Christmas Bells Ad