An 80-year-old Mandan man spent about 28 hours tied up in his apartment, and police are searching for a suspect.

Mandan Police Lt. Paul Leingang said one of the man's neighbors at Liberty Heights, an apartment complex for retired people at 1500 Third Ave. NW, noticed the man had not been at lunch on Monday or Tuesday. The neighbor also noticed the man's television and lights were left on late Monday night, which was unusual, Leingang said.

The neighbor told the housing authority about his observations, and maintenance entered the apartment around 3 p.m. Tuesday, Leingang said. They found the man lying on the floor of his apartment with his arms and legs tied behind his back, Leingang said.

He said the man said a man he had met on at least one other occasion had opened the door to his apartment at around 10 a.m. Monday, walked in and greeted him.

After the acquaintance entered, he hit the 80-year-old man over the head from behind, knocking him to the floor, Leingang said. He said the acquaintance then tied up the man, stole his wallet and left.

"The victim was bound until almost 3 o'clock Tuesday afternoon," Leingang said.

The man spent the night in the hospital, and Leingang did not know when he would be released. He said the man had a head injury, was dehydrated and had injuries on his wrists and legs from being bound.

The attack appears to have been planned to some extent, Leingang said.

"We don't know for sure, but it doesn't appear to be a random thing," he said.

Leingang advises people to keep their doors locked and look out for one another.

Police are searching for the suspect in the robbery. He is described as a white man in his late 20s to mid-30s with dark hair, a mustache and possibly a goatee.

The man is between 5-feet-9-inches tall and 6-feet tall. He is lean with an average build and somewhat of a pot belly.

Anyone with information about the robbery or the suspect should call the Mandan Police Department at 667-3455 or Bismarck Area Crime Stoppers at 224-TIPS (224-8477).

(Reach reporter Jenny Michael at 250-8225 or jenny.michael@bismarcktribune.com)