The transgender Rhode Island maniac who murdered his ex-wife and one of their sons at a high school hockey game had vile neo-Nazi tattoos on his bicep.

Photos show that twisted Robert Dorgan, 56, who went by the name Roberta Esposito, inked a large SS symbol on his right arm, representing the Schutzstaffel paramilitary organization under Nazi Germany.

The symbol was frequently used in Third Reich propaganda and signage.

In the middle of Dorgan’s arm tattoo featuring bright-red pseudo-runic letters appears a white skull and crossbones with glowing red eyes, known as the Totenkopf, or “death’s head” skull.

According to the Anti-Defamation League, in Nazi Germany, the death’s head was a symbol of one of the branches of the SS “whose purpose was to guard the concentration camps.”

The ADL said it’s a common hate symbol displayed by neo-Nazis and other white supremacists “because of its importance to the SS.”

Dorgan had a history of spewing antisemitic and racist rhetoric on social media.

The day before his rampage at the hockey rink, Dorgan posted an anti-Asian slur as he replied to a video praising Adolf Hitler, saying, “Really nice but a c—k made that song.”

In other replies, he made repeated references to “white power” and “white pride world wide.”

He also retweeted footage of people doing the “Sieg Heil” Nazi salute.