The police, who conducted the raids wearing masks and strapped with heavy weapons according to the Associated Press, are questioning nine others in connection with the missing coin. The four main suspects are related and between 18 and 20 years old.
The coin was not recovered in the operation.
“We assume that the coin was partially or completely sold,” Carsten Pfohl of the Berlin state criminal office said at a news conference. Police are picking apart clothes and vehicles used by the suspects to find traces of gold left behind.
The orchestrated raid is the latest wrinkle in the coin's journey from Canada to the Bode to the hands of at least two thieves, who stole the coin in a brazen nighttime heist on March 27 that sounds more like a heist film than a museum robbery.
An elevated railroad near the building aided the burglars, who used a ladder to climb into a museum window and slip into the exhibit. According to AP, police said an insider may have helped identify the coin, which was stolen as other exhibitions remain untouched. The museum, with more than 500,000 items, is home to one of the world's largest coin collections.
Once out of the museum, the thieves loaded the 1.2-inch thick, 20.9-inch in diameter coin into a wheelbarrow, slipped into a park using a rope and fled in a getaway car, the AP reported.
The coin, bearing the head of Queen Elizabeth II with an obverse bearing a maple leaf is a reproduction of the original, which was produced by The Royal Canadian Mint in 2007 with a face value of $1 million (Canadian).
Nicknamed “The Big Maple Leaf,” the Guinness Book of World Records named it the world's largest coin, according to the mint's website. Its 99.999 percent purity and gold content boosts the actual value to about $3.9 million in U.S. dollars, according today's gold price index.
The mint does not track coins after they are sold, Alex Reeves, a spokesman for the mint, told The Washington Post. Five replicas of The Big Maple Leaf were sold privately, Reeves said, including the one stolen from the Bode Museum.
The coin is “about the size of a manhole cover, more or less,” Reeves said. The original remains at the mint.
The museum did not immediately return requests for comment.
“Why did the Royal Canadian Mint make the world's purest and largest gold bullion coin?” the mint's website asks rhetorically.
“Because we can,” the mint, and apparently the thieves, answered.