Four masked, machete-wielding suspects are known to have made off with around €242,000 in cash from the luxury Grand Hyatt hotel, which was hosting the European Poker Tour on Saturday afternoon. The competition started on Tuesday with nearly 1,000 players, including German tennis legend Boris Becker.

But because the well-timed heist bore the signs of an amateur job, police told Berlin daily Berliner Zeitung that they now believe there was at least one other accomplice already inside the hotel who gave a signal to begin the raid.

“The suspects struck at the exact moment when the money was being prepared for transport at the main safe,” a police spokesperson told the paper. “A few minutes before or after and they would have had no chance.”

Police are also hoping to clarify why several security personnel happened to be taking their lunch break at the time of the robbery, when the four-person gang, armed with handguns and machetes, burst into the hotel, threatening security staff and sparking a panic.

Images of the chaotic scenes during the raid were broadcast on television, showing furniture overturned and poker players hiding under tables and trying to escape.

Amid the chaos, one of the security guards managed to tear a bag full of cash from the robbers. Seven people sustained minor injuries in the crush.

In addition to mounting pressure the police hunt, the suspects are likely also experiencing stress from within their “underworld” because of their amateur status, an unnamed security expert told Berliner Zeitung.

“And when such semi-professionals land a coup like this, then the desire for a piece of the pie grows among the real big guys in the underworld,” he said.