CNN  — 

An 11-year-old boy died after he fell into the water and was swept into a storm drain during a flash flood in northwest Arkansas Monday evening, according to police.

An adult who tried to save the boy also was swept into the drain and was rescued, officials said.

The boy drowned after he “accidentally fell into the water and the current swept him under,” Bentonville Police Corporal Adam McInnis said in a news release.

Bentonville fire and police crews were called to assist “two people that had been swept into a storm drain by floodwaters” at around 5:30 p.m. Monday, police said.

Shortly after arriving, rescue personnel found a 47-year-old woman “and removed her from the storm drain,” police said. She was taken to a hospital and her current condition is unknown.

First responders continued their search and found the 11-year-old boy, according to the news release. “The child was transported to a local hospital where he ultimately died,” police said.

Initial reports indicate the child was playing near a retention pond where storm water gathers during heavy rain, according to deputy fire chief Kevin Boydston.

The child fell into the water and the current swept him under, McInnis said. The woman jumped into the water to save the boy and was swept away as well, Boydston told CNN.

The incident is under investigation.

There was heavy rain and thunderstorms in Bentonville on Monday evening. Over 1.5 inches of rain were recorded in the 5 p.m. hour at the Rogers Executive Airport, just east of Bentonville.

CNN Weather’s Monica Garrett contributed to this report.