presented at trial showed that on the morning of November 3, 1976, Mrs. Doris Polka was attacked and beaten in her real estate office in Newbury. Her assailant bound and gagged her with rope and tape, blindfolded her, and took her to the third floor of a house behind the office, where she was ultimately found by her husband and a police officer. At the hospital, the victim told police investigators that the assailant wore dark blue slacks, a maroon nylon jacket, and heavy yellow rubber gloves, and had covered his head and face with a mosquito net. She also stated that during the altercation she had stabbed the assailant's leg and broken his silver expansion watch band. Upon police questioning about possible suspects, she told them thata Dr. Osborne had visited the realty office daily for two weeks including a three-hour visit the previous afternoon. With assistance from the postmaster and the chief of police, Lt. Wilson determined that the defendant resided in a cottage at a motel. At about 6:45 p.m. on the evening of November 3, 1976, Lt. Wilson and Trooper Garvin went to the motel, and the proprietor pointed out the defendant's cottage. All the lights were on in the cottage, but no car was parked in the defendant's space. The officers knocked and called but got no response. Thinking that the defendant, if he had been the assailant, might have a serious leg injury and need assistance, Lt. Wilson opened the unlocked door and entered the cabin. Inside, he noticed