(Adds background, details from filing, byline)
NEW YORK, Aug 8 (Reuters) - U.S. prosecutors on Tuesday moved to drop their criminal case accusing Benjamin Wey of running a fraudulent stock manipulation scheme, after a federal judge threw out much of the evidence they hoped to use against the Wall Street financier.
The dismissal request was the second in three weeks in a high-profile case handled by the U.S. Attorney's office in Manhattan.
It followed prosecutors' request on July 21 to end a separate case against two former JPMorgan Chase & Co traders in the London Whale trading scandal.
Prosecutors had accused Wey in September 2015 of making tens of millions of dollars by secretly controlling large blocks of shares in shell companies that went through so-called "reverse mergers," manipulating the companies' stock prices, and then selling shares at artificially high levels.
But the case collapsed after U.S. District Judge Alison Nathan on June 13 suppressed a huge cache of materials seized from Wey's home and offices, saying the broad search warrants violated his constitutional right against illegal searches and seizures.
Nathan said "blanket suppression" was necessary because the seizure of items such as children's school records, family photos and X-rays at minimum reflected "grossly negligent or reckless disregard of the strictures of the Fourth Amendment."
In Tuesday's filing, prosecutors said they decided to dismiss the charges against Wey because the case had been "based in significant part" on the seized materials, and "the government can no longer rely on that evidence at trial."
The dismissal requires court approval. A spokesman for Acting U.S. Attorney Joon Kim in Manhattan declined to comment. (Reporting by Jonathan Stempel in New York; Editing by Richard Chang and Grant McCool)