A father and son from Chicago’s south suburbs drowned on Lake Michigan in Porter County, Indiana, during the July 4th weekend, according to law enforcement.

At around 4:20 p.m. on Saturday, conservation officers with the Indiana Department of Natural Resources responded to an active water rescue near Dunes Acres adjacent to the Indiana Dunes National Park. The rescue took place in a remote area, which required conservation officers to utilize off-road vehicles and a patrol boat, officials said.

By the time conservation officers reached the scene, both men had been removed from the water by a good Samaritan, the Indiana DNR stated in a news release. Conservation officers and National Park Rangers brought both men to the Port of Indiana by boat while performing CPR, officials said.

The victims were identified as David Meneou, 65, of Joliet, and Jameson Meneou, 20, of Lockport, the DNR stated. A preliminary investigation revealed both men were in the water when Jameson entered deep water and began to struggle. At that point, David attempted to rescue his son but also started to struggle.

The incident remained under investigation Sunday evening.