Fears of voter fraud only increased this week, after a California man found a stack of 83 mail-in ballots shipped to a single neighbor's apartment.

Jerry Mosna of San Pedro found the two stacks of ballots on top of his mailbox on Saturday. All of the 83 ballots were unused and addressed to different people, all supposedly living in an apartment he knows to be occupied by a single, 89-year-old, neighbor.

'I think this is spooky,' Mosna told Fox News. 'All the different names, none we recognize, all at one address.'

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A California man found these two stacks of mail-in ballots sent to a single woman's address in his apartment complex this weekend

Mosna says that his neighbor lives by herself in a two-bedroom apartment so small that eighty people couldn't even fit in the apartment.

So he and his wife Madalena took the ballots to the Los Angeles Police Department, hoping they would investigate.

Instead, police sent them to the post office to report the incident.

Mosna left the police station feeling certain that the ballots would not be investigated and he's now certain that voter fraud is going on.

'Yes, there is voter fraud. We saw it with our own eyes,' Cracchiolo said.

Jerry Mosna, right, and his neighbor John Cracchiolo, left, alerted authorities about the incident

One of Mosna's other neighbors, John Cracchiolo, contacted the Los Angeles County Registrar's Office, who said they were investigating.

In a statement, the office said: 'We are carefully reviewing our records and gathering information to fully identify what took place. Our preliminary assessment is that this appears to be an isolated situation related to a system error that occurred causing duplicate ballots to be issued to an address entered for a single voter. We are working directly with the system vendor to ensure the issue is addressed and to identify any similar occurrences.'

The spokesman would not say comment on the exact number of incidents that had happened, other than to say 'relatively few'.

A spokesman for the Postal Service indicated that all 'improperly addressed ballots had been returned to our office'.

As the presidential campaign has reached its final weeks, Donald Trump has repeatedly claimed that voter fraud could swing the election in Clinton's favor.

However studies have shown that while voter fraud does happen in the U.S. - it is not significant enough to make a difference in an election.

At a rally last month, which was interrupted repeatedly by protesters, Trump cited research from the Pew Center that had been featured in a report meant to highlight antiquated voter registration systems 'plagued with errors and inefficiencies.'

The 2012 study found that approximately 24 million - or one of every eight - voter registrations were no longer valid or significantly inaccurate. It also found that more than 1.8 million dead people were listed as voters and that approximately 2.75 million people were registered in more than one state. But the report cited no evidence that those errors had contributed to any significant voter fraud. Instead, it pointed to estimates that at least 51 million U.S. citizens are eligible but not registered to vote.

Trump also cited a controversial 2014 op-ed in The Washington Post by a group of professors at Old Dominion University promoting their research concluding that 'enough' non-citizens have voted in recent elections that their participation could plausibly change the outcome of close elections.

Among their claims: Because non-citizens tend to favor Democrats, their votes could have been responsible for President Barack Obama's 2008 victory in North Carolina.

There is no evidence the latter is the case - and the article spawned so much backlash over its methods and conclusions that the authors were prompted to issue a follow-up defense.