Authorities found a body Monday in the Kansas River they believe to be a Leavenworth man who has been missing since Sunday morning.

The Douglas County Sheriff’s office reported Monday afternoon that the body was discovered by a sheriff’s deputy at 9:30 a.m. near the east bank of the Kansas River, about two miles west of the Kansas River bridge near Lawrence’s downtown.

Sheriff’s office personnel assisted the Kansas Parks and Wildlife Department in recovering the body.

A positive identification is pending the county coroner’s report, the sheriff’s office said.

Thomas B. Portenier Jr., 38, has been missing since about 5 a.m. Sunday, when he got into a motorized fishing boat and left three companions who had been camping with him along the river about 2.5 miles northwest of the Bowersock Dam.

A short time later, the other campers heard the sound of a crash and the boat’s motor running full throttle. They used a mobile phone to call 911.

Sheriff’s officers were joined by firefighters from the Lawrence-Douglas County Fire & Medical in the search along the river. They found the boat but could not find any sign of Portenier until Monday morning.