MADISON, Wis. - Police say a contractor who suffered a fatal heart attack while working overnight at a Wisconsin Culver's was "scared to death" when two armed men tried to rob the restaurant.

  

Madison Police Chief Mike Koval told reporters Tuesday that the robbers would not allow other workers to help the 56-year-old man, who was suffering a medical emergency.

  

Authorities say the two masked robbers entered the restaurant about 3 a.m. while four men were working on a remodeling project. Police say one robber targeted the restaurant's safe while the other robber held the men at gunpoint.

  

Koval says the robbers held the men captive for up to an hour.

  

The victim's name was not released. Authorities consider his death a homicide.