WASHINGTON CROSSING, Pa. (AP) — The active search has ended for a 9-month-old boy swept away in a flash flood that killed his 2-year-old sister and mother as well as four other people in southeastern Pennsylvania earlier this month, authorities said Wednesday.

Divers found no sign of Conrad Shiels’ body when they searched the last remaining areas where the flooded creek enters the Delaware River. Search dogs were used to scour islands in the river as well as its banks, while marine units scanned the river and both the Pennsylvania and New Jersey banks, Upper Makefield Township police said.

“At this point, we have exhausted all means of attempting to locate Conrad,” police said in a Facebook post late Wednesday afternoon. “With broken hearts, we regretfully announce that the active search for Conrad has concluded.”

Hundreds of people took part in the search with the aid of dogs, boats, divers, sonar, air units and drones as well as heavy equipment, police said.

Last weekend, the body of Conrad’s sister Matilda Sheils was found in the river near a Philadelphia wastewater treatment plant, about 30 miles (50 kilometers) away from where the flash flood slammed into the family’s car on July 15. They had traveled from they home in Charleston, South Carolina, to visit relatives and friends in the area, and were on their way to a barbeque.

The children’s father, Jim Sheils, grabbed the the couple’s 4-year-old son, while their mother, 32-year-old Katie Seley, and a grandmother grabbed the other children, Brewer said. Sheils and the older boy made it to safety, but Seley and the grandmother were swept away along with the younger children. The grandmother survived but the mother died.

“Although, at this time, we were unable to reunite Conrad with his loving family, he will forever live in our hearts and he will never be forgotten,” police said Wednesday.

Police said the family had been made aware and had expressed “deepest gratitude” to everyone who helped with the search, and to all others for their “outpouring of love, support, and kind words during this extremely difficult time,” police said.

Four other people drowned in the flooding about 35 miles (60 kilometers) north of Philadelphia, according to the Bucks County Coroner’s office: Enzo Depiero, 78, and Linda Depiero, 74, of Newtown; Yuko Love, 64, of Newtown; and Susan Barnhart, 53, of Titusville, New Jersey. Ten other people were rescued from their vehicles amid the flood, police said.