Police are investigating after the headquarters for Donald Trump’s campaign in Massachusetts was spray-painted with lewd words and images.

The graffiti had vulgar and sexual references, and one portion referred to the Republican presidential candidate as a “Nazi.” The word “pig” also appeared to be spray-painted across a window of the headquarters.

A woman reported the graffiti to police at about 9 a.m. yesterday, police said.

Littleton police Chief Matthew J. King promised “a full and thorough investigation” and condemned the vandalism.

“These types of acts are surprising and certainly not representative of the kind of town that Littleton is and the kind of people who live in this community. People have a right to express their views and disagreements, but the line is drawn at criminal behavior and vandalism,” King said in a statement. “Littleton is an accepting place full of people who coexist regardless of each other’s political ideology. I speak for the entire community in my strong condemnation of these acts, and I promise a full and thorough investigation.”

Town officials also swiftly chimed in.

“This behavior is not representative of either Littleton or its residents,” said Jim Karr, chairman of the Littleton Board of Selectmen in a statement. “This is not what Littleton is all about. I hope that the Littleton Police Department identifies and prosecutes whomever is responsible for these acts to the fullest extent of the law.”

Trump has campaigned vigorously in Massachusetts, vowing to fight hard for Republican primary votes here and drawing large crowds to rallies in Lowell and Worcester.

The Trump campaign referred questions to a national spokeswoman, who did not return calls for comment yesterday.

Police said the investigation will include reviewing surveillance footage from other businesses in the area.

Anyone with any information is asked to call Littleton police at 978-540-2300.