MONROE, Wis. (CBS 58) - A 72-year-old Wisconsin man died after drowning while attempting to rescue an injured bald eagle from Lake Petenwell, according to authorities.

The Adams County Sheriff's Office said deputies received a missing persons report shortly after 1 p.m. on June 24. Family members reported that Robert R. Marti of Necedah had been missing since about 5 p.m. the previous day after fishing near the Browndeer Drive boat launch in the Town of Monroe.

Investigators learned Marti had spotted an injured bald eagle in the water and contacted the Wisconsin Department of Natural Resources and a raptor rescue facility. He was told responders would come the following morning.

According to the sheriff's office, Marti later told a family member he planned to return to rescue the eagle himself.

When deputies arrived at the boat launch, they found Marti's locked vehicle and equipment believed to have been intended for rescuing an injured animal.

Authorities searched the area using drones, boats and ground crews before recovering Marti's body just offshore around 6:15 p.m. Investigators also found a large fishing net and eagle feathers nearby.

A preliminary investigation determined Marti became entangled in underwater debris near the shoreline and drowned. Authorities noted he was not wearing a life jacket.

The investigation remains ongoing.