Armed robbers used automatic weapons and a fake bomb to carry out the daring raid.

The scene of the 1989 robbery, outside of what is now a Bremer Bank on Singletree Lane. Google Streetview

One of the most brazen armed robberies in Minnesota history remains unsolved 30 years later, and the anniversary has prompted another appeal from police.

It was at 1 p.m. on Apr. 18, 1989, that a Ram Security guard was loading cash into an armored truck outside the First State Bank of Eden Prairie – now a Bremer Bank – on Singletree Road, when a car and a van pulled up simultaneously.

The car pulled up behind the truck, the van in front, blocking its path, while two masked men carrying machine guns jumped out of the car and attacked the guard at the back of the truck, while a third suspect stayed in the car.

They overpowered him and entered the truck, removing almost $1 million in cash.

Meanwhile, a fourth suspect placed a bomb-like device on the hood of the car, before they fled in the two vehicles.

It turns out, the bomb was a fake, and had been placed on the truck as an ingenious diversion, occupying police time while the robbers made their getaway.

Their vehicles were later found in Eden Prairie and Burnsville but the suspects were never found, and neither was the money.

An investigation led the FBI to describe the robbery as a "professional job," and it even featured on an episode of NBC's "Unsolved Mysteries" in 1990 (which you can watch below).

On the show, it was noted that the fake bomb was almost identical to one used in another robbery in Baltimore, Maryland, in which more than $600,000 was stolen.

A year later, a similar robbery happened outside a First State Bank in Burnsville, that authorities believe may have been connected to the same robbers.

Eden Prairie police have re-issued an appeal for information, and wants anyone with a tip to call them on 952-949-6200, or the FBI on 763-569-8000.