The Mark Twain House & Museum in Hartford has been vandalized three times since Dec. 23, with windows broken by bricks, rocks and chunks of asphalt, the executive director of the historic house museum said Wednesday.

Pieter Roos said the thrown objects damaged not only windows but also “sheared off three fingers of a 19th-century marble statue, a Venus de Medici, that was on long-term loan from the Wadsworth Atheneum.”

Roos said in the first attack, on Dec. 23, “a group of three individuals ... started with very small rocks and broke some small holes in the conservatory windows. We had those repaired and hoped it wouldn’t happen again.”

On Dec. 31, just before midnight, a group of three that appeared to be the same three individuals struck again, he said.

“They escalated their attacks using larger rocks and chunks of asphalt and broke some more windows,” he said. The objects again were thrown into the conservatory, and one of the rocks went farther, flying into the area of the Conservatory arch and hitting the statue.

The most recent attack was Tuesday night.

“This time they have moved up to bricks. They took them out of our own garden. They put a lot more holes in the windows again,” Roos said. Again, the conservatory was the focus of the attack, as well as the Mahogany Suite.

Roos said repairing the damage will cost thousands of dollars, not just the statue and the window glass, but the “muntin bars” that divide the windowpanes, which are original to the house.

The 11‚500-square-foot, 25-room, three-story Victorian Gothic mansion at 351 Farmington Ave. was the home of the author, whose real name was Samuel Clemens, and his family from 1874 to 1891.

While living there, Clemens wrote “The Adventures of Tom Sawyer,” “The Prince and the Pauper,” “Life on the Mississippi,” “Adventures of Huckleberry Finn,” “A Tramp Abroad” and “A Connecticut Yankee in King Arthur’s Court.”

A GoFundMe campaign was started on Wednesday to accept donations to repair the damage. The link is gofund.me/a4a602e9. Roos said, however, that the Twain House is uncertain how to proceed with fixing the damage, considering it could happen again.

“There’s a real feeling of helplessness involved here. They come in, hit fast and leave. What can you do about it? We’d have to have someone positioned outside to keep them from doing it again. Contracted security is expensive and something we’ve never needed before. But still, by the time you hear the breaking glass, they’ve disappeared down the hill in a matter of seconds,” he said.

He said the Twain staff is also distressed by the loss of respect for the revered institution.

“We’ve always depended on the honesty of [the] neighborhood, but somebody out there wants to be up to no good right now,” he said. “This is a national landmark. It is one of the marquee historical museums for the state and one of the principal tourist destinations in the city of Hartford. We like to live in this neighborhood, but it’s disturbing that someone would randomly do this type of damage.”

Anyone with information about the incidents can contact Hartford Detective Sid Palmieri at 203-400-9265 or palmc002@hartford.gov, or Detective Anthony Buccher at 860-757-4175 or bucca001@hartford.gov