'criminal scheme' is correct and usable in written English.
You can use it when referring to a plan to do something that is illegal. For example: The criminal scheme involved breaking into the bank and stealing money.
"This was a continuing criminal scheme".
The police eventually linked that killing to an unrelated criminal scheme involving cars.
"We must not let her take her criminal scheme into the Oval Office".
"He certainly sought to benefit himself in this criminal scheme," Shugart said.
The financial practice originated not as a criminal scheme but as a way to help the terminally ill.
He built a case that Walker and his campaign organization Friends of Scott Walker carried out "a criminal scheme".
"Ken Lay took the helm of the criminal scheme," said Andrew Weissmann, head of the Justice Department's Enron Task Force.
"We must not let her take her criminal scheme into the oval office," he told a rally in New Hampshire.
Investigators were looking into the possibility that the theft could be part of a larger criminal scheme, Ms. Manners said.
"Ceglia used the federal court system to perpetuate his fraud and will now be held accountable for his criminal scheme," said Orin Snyder, a partner at Gibson Dunn.
Federal prosecutors countered the defense's argument by calling Ms. Chiesi the "consummate Wall Street insider" who engaged in a "broad and far-reaching" criminal scheme.
