The number of apparently illegally printed ballots for Bulgaria's May 12 early general elections has swollen to at least 400,000, according to an announcement by the prosecution.

The 'fake ballots' scandal erupted just a day before Bulgarians went to the polls, as the prosecution announced that law enforcement officials had seized a surplus of 350,000 ballots at a printing house.

The leading hypothesis is that the ballots, which comply to official standards, are illegal, as they have been printed in excess of the official order by the government.

The prosecution still has to determine whether the ballots were not actually intended to be destroyed, and whether they were intended to organize a manipulation of election results.

It also has to determine how exactly it came about that so many surplus ballots were printed, and whether there will be grounds to charge government officials for negligence or malpractice.

The full count of the 'fake ballots' is expected to be completed by Friday, whereas the full initial invesigation of the case is expected to be over "within months," according to prosecutor Stoil Toichev, as reported by bTV.

"Apparently someone did not fulfill his or her duties in office. It is to be determined whether this was done on purpose or was a case of negligence," said Toichev, who is in charge of the investigation.

The 'fake ballots' scandal led to a number of parties lashing out at former ruling party GERB, saying they intended to rig the vote.

The string of political press conferences given on the so-called reflection day has led GERB, who actually came out first at the vote, to file with the Constitutional Court a claim for cancellation of the results, on the grounds that a legislative requirement for no canvassing on reflection day had been broken.