Berlin - German police on Wednesday arrested four suspects they linked to an Arabic criminal clan over the spectacular theft of a giant 100kg gold coin from a Berlin museum early this year.But they found no sign of the loot - Canada's "Big Maple Leaf" coin, which has a face value of one million Canadian dollars and is estimated to be worth €3.75m on the gold market.Police fear the treasure "was either cut into small pieces or taken abroad" since the March 27 night-time heist, said Carsten Pfohl of the Berlin criminal police office."Unfortunately we have to presume that it was sold off in parts or whole," he said at a press conference."My hope that we'll recover even parts of the coin is unfortunately relatively low."Around 300 police took part in dawn raids at 14 locations, including apartments and a jeweller's shop in Berlin's Neukölln district and targets in surrounding Brandenburg state.Police said the four unidentified suspects, aged 18 to 20, and nine other suspects were all members of, or closely connected to, a Berlin organised crime group with an Arabic family clan at its core.Two service staff at the state body that runs Berlin's museums were among those being investigated by police, the body's chief of security Hans-Juergen Harras told the national news agency DPA.'History forged in metal' The thieves stole the huge coin from the Bode Museum on the capital's Museum Island, close to Chancellor Angela Merkel's apartment, on March 27. The commemorative coin was issued by the Royal Canadian Mint in 2007 and features a portrait of Queen Elizabeth II.The thieves used a ladder, rope and a wheelbarrow to carry away the metal disk with a diameter of 53cm, which a private individual had loaned to the museum.It was probably damaged when the thieves dropped it twice - once onto rail tracks that pass the museum and cross the Spree River, and again in Monbijou park on the opposite river bank, from where they sped off in a car.Video surveillance footage from a nearby railway station released by police this month showed three men wearing dark clothes, their faces obscured by hoodies, high collars and their hands.Berlin's chief prosecutor Martina Lamb said the footage also showed the suspects making previous scope-out trips for the heist, on March 17 and 21, before carrying out the theft.The Bode Museum, which has a collection of coins and medals billed as a "chronicle of human history forged in metal," also showcases Byzantine sculpture and paintings.