One crime that is under prosecuted is the offense of sham immigration marriage. One reason is that the United States government lacks the resources to investigate and prosecute this crime.
One instance in which the defendants did not avoid criminal prosecution is United States v. Thiongo, 344 F. 3d 55 (1st Cir. 2003). In the appeal the First Circuit affirmed convictions arising from a conspiracy to gain illegal admission into the United States for Kenyan nationals, holding there was no abuse of discretion in permitting the prosecutor to ask the defendant on cross-examination whether she served as a legal witness to a sham marriage (between her current husband and another woman) designed to avoid immigration laws. The Court found that willingness to do so "is fairly probative of Defendant's truthfulness."
GREGORY CHANDLER, Attorney at Law