WASHINGTON (AP) — North Dakota authorities plan to pursue charges against Green Party presidential candidate Jill Stein for spray-painting construction equipment at a Dakota Access Pipeline protest.

Morton County Sheriff Kyle Kirchmeier said Tuesday that the charges would be for trespassing and vandalism. State court records Tuesday evening didn’t yet list any formal counts against Stein.

A spokeswoman for Stein says that activists invited her to leave a message at the protest site. She says Stein wrote “I approve this message” in red spray paint on the blade of a bulldozer.

Stein, who is anti-war and advocates for clean energy, camped out with protesters Monday evening.