Clashing with the U.S. Attorney’s Office in Boston, dozens of defense attorneys for clients charged in the college admissions scandal accused prosecutors Tuesday of using improper judge-shopping tactics to steer their cases.

In a letter sent to U.S. District Chief Judge Patti Saris of the District of Massachusetts, 26 lawyers who represent parents charged in Operation Varsity Blues expressed concern that prosecutors would subvert the random judge-assignment process by adding defendants to a case where the judge was already assigned.