New York (CNN) A major US investigation into Russian money laundering has come to an abrupt end.

The case aimed to expose how Russian mobsters allegedly stole $230 million and hid some of the cash in New York City real estate. Also sure to come up was the suspicious death of the Russian lawyer who exposed the alleged fraud, though US prosecutors weren't alleging that the defendants were behind it.

The trial was set to start on Monday, but late Friday night, federal prosecutors in New York announced they settled the case with Prevezon, the company accused of buying up "high-end commercial space and luxury apartments" with laundered money.

The abrupt conclusion has some involved in the trial wondering why this Russian investigation had been cut short.

"What most concerns me is: Has there been any political pressure applied in this?" asked Louise Shelley, an illicit finance expert who was set to testify in support of the US government on Tuesday.

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