Police said the incident happened shortly after 11 p.m. Saturday on Hillside Avenue when a woman reported she was woken up by a man in her bedroom who was armed with a knife.
The man allegedly threatened her with a knife and assaulted her multiple times before she managed to flee.
The woman was later taken to a local hospital for treatment.
Police are still searching for the suspect. He is described as a white man between 5’5' to 5’6" tall. He is about 40 years old with short brown hair, a thin build, and a light complexion with a seasonal tan.
Anyone with any information is asked to call the Merrimac Police Department at 978-346-8321.