By Eliott C. McLaughlin, CNN

(CNN) -- Authorities working in flood-ravaged Maryland found the body of a missing Army National Guardsman in the Patapsco River, just east of the heavily damaged town of Ellicott City on Tuesday, the Howard County Police Department said.

Since Sunday evening, rescuers had been searching for Sgt. Eddison Hermond of the Maryland Army National Guard.

The 39-year-old assigned to Camp Fretterd Military Reservation in Reisterstown was at a Mexican restaurant in Ellicott City's historic downtown area when the flooding began, said Sarah Lopez, whose husband met Hermond 20 years ago in the US Air Force.

Lopez, who was attending a birthday party with Hermond and her husband, said Hermond left the party to help a woman rescue her cat. Witnesses returned and said Hermond slipped into the river and was carried away, she said.

"(The people with Hermond) saw him go under the water and not surface," police Chief Gary Gardner told reporters.

2016 was bad; latest flooding 'even worse'

Hermond joined the Air Force in 1996 and served 10 years as an airman, the Guard's Col. Charles Kohler said. The Severn, Maryland, native joined the Guard in 2009. He was not on duty when he disappeared,

Residents and business owners were being allowed to return to the hardest-hit areas Tuesday to collect their personal belongings.

The town, which experienced major flooding in 2016, was inundated again this week when the Patapsco River reached a record level as rain pounded the greater Baltimore area.

"There are a lot of people whose lives are going to be devastated again, and they've been working so hard to come back," Howard County Executive Allan Kittleman said. "I can't imagine what they're going through. I couldn't imagine what they went through two years ago, and now it's even worse."

Emergency responders conducted 300 rescues, about 30 of them water rescues. A major water main broke, and the flooding washed out a sewer line.

Gas and electricity have been shut down on Main Street, where water ran through buildings as if it were a tributary of the nearby Patapsco, which swelled to record levels during Sunday's storms. The river is a major waterway that feeds into the Chesapeake Bay.