An intensive search resumed early Monday to find Radivoje Ray Novakovic, a 75-year-old Hugo man with medical issues who left for a walk about 7 p.m. Sunday and didn't return.

"We really do not have a defined search area," said Washington County Sheriff Bill Hutton. "He's a daily walker. He typically walked 3 to 4 miles a day along a couple of different paths. Those are the areas we're hitting."

Novakovic, wearing a maroon shirt, khaki pants and a brown hat, left his home in the 13000 block of Europa Trail N. in the southern part of the city near the north end of Bald Eagle Lake for his usual walk.

When he didn't return, family members searched, then called the sheriff's office about 10 p.m. Searchers worked until about 4 a.m. Monday to locate him, then resumed the effort four hours later, Hutton said.

Novakovic is approximately 5 feet, 6 inches tall and weighs 160 pounds and with gray/white hair. He has been diagnosed as being diabetic and is mildly bipolar. His diabetes is the greatest concern, Hutton said. Fluctuations in blood sugar can cause disorientation, along with creating bursts of energy allowing him to stray farther away.

The State Patrol helicopter joined Monday's search, which included sheriff's deputies, the Washington County Sheriff's Office Mounted Patrol, Water Patrol and canine units, Centennial police officers and fire departments from Hugo, Forest Lake, Bald Eagle Lake and Centennial.

Searchers systematically knocked on doors in the area, and Hutton is asking nearby residents to do thorough searches of their own properties for any sign of Novakovic. He could have sought shelter in an outbuilding, or a vehicle parked in a garage.

At this time, there is no indication of foul play and the Sheriff's Office is not requesting volunteers to assist searching.