All of the ballots were submitted in Lancaster County, but two other counties are scrutinizing similarly suspect batches. While officials say it's the work of a "large-scale canvassing operation," they're not yet saying who's behind it. 

The roughly 2,500 applications landed at or near Pennsylvania's Oct 21 registration deadline; some observers are speculating that the timing may have been tactical, with the intent of exploiting time-pressure administrators would be under ahead of the Nov. 5 Election Day. However, as they examined the massive heap of forms, application processors were immediately alarmed by what they saw:

Multiple applications with the same handwriting and signatures
Many forms filled out on the same day
Applications for previously-registered voters whose signatures on the forms did not match the ones on file 

That prompted a police investigation, and Lancaster County detectives soon confirmed many of the applications were fraudulent. Indications of fraud included: 

Inaccurate addresses

False personal identification information

False names

Names that didn't match the Social Security Number on the form

In many cases, forms had accurate data, but the supposed applicants told detectives they had neither requested nor completed the forms, and confirmed that the signatures were not theirs. In all, 60% of the applications that have been vetted so far were found to be fraudulent.