Leach previously claimed that Margolies spent more than $70,000 of general election funds this year on the primary race. On Monday, he said Margolies had since spent an additional $15,000 in donations that were not supposed to be used until the general election. "This is a blatant and dramatic flouting of the law," Leach said.
Margolies has denied the accusations. Her campaign said Monday that Leach's campaign had failed to take into account $78,500 in unspent money that the campaign reported as a separate "Media Account."
"Marjorie 2014 used an acceptable accounting method to distinguish between general and primary funds, and at no time did Marjorie 2014 access general election funds for expenditures in this primary," campaign treasurer Jennifer May said in a statement.
Ken Smukler, a senior adviser to Margolies, last month called Leach's attack an attempt "to save his desperate campaign."
Margolies also said Leach had misled voters by claiming that he is "not a millionaire" in campaign ads because all the high-value assets he has reported belong to his wife, citing a $250,000 home equity loan he recently made to his campaign.
Margolies has also been taking shots at Boyle for his voting record on women's issues. On Monday, she called on the federal political action committee Building a Better Pennsylvania to disclose the sources of money the group has spent in the 13th District race. The group has run TV ads backing Boyle that portray him as a protector of women's rights, a description that his opponents have disputed.
Spokesman Ken Snyder said that Boyle was pro-choice and that the committee paying for the ad was made up largely of building trade unions.