Rep. Jake Auchincloss (D-MA) slammed his party’s own Senate candidate in Maine on Monday night, refusing to endorse Democratic oyster farmer Graham Platner over his controversial tattoo that closely resembled Nazi imagery.Platner, the only remaining candidate running for the Democratic Senate nomination in Maine, has caught heat over the past several months for once sporting a now-covered-up tattoo of an image largely associated with the Nazi’s infamous Death’s Head symbol. “I find that tattoo and his commentary about it to be personally disqualifying,” Auchincloss, a Jewish Democrat, said in a CNN interview. “I hope Maine voters agree with me.”

The symbol was used in the Holocaust by Adolf Hitler’s SS-Totenkopfverbände, the unit responsible for the Nazi’s concentration camps. Platner has said he did not know the meaning behind the symbol, telling the public that he received the tattoo in his 20s while drinking with his fellow Marines. Platner has said they chose the tattoo because it was “a terrifying looking skull and crossbones” and that he is “not a secret Nazi.”

Auchincloss previously called on Platner to drop his bid in the Senate race last October, weeks after Gov. Janet Mills (D-ME) announced her candidacy in the Democratic primary in the race. However, Mills has now dropped her bid, making Platner the only candidate in the Democratic field and clearing the way for him to take on incumbent Sen. Susan Collins (R-ME).