Witness to Murder, by Norman Firth (epub/Kindle)

Closing her curtains, June Merrill catches sight of a woman in the adjoining flats also preparing for bed. June sees her begin speaking to someone unseen then cower back in her bed. June saw a man approach the woman on the bed, apparently demanding something to which the woman would not agree. Suddenly his arm rose, then slashed down, holding what looked like s scalpel. When he moved away, the woman lay dying, the sheets a red mass of blood. Turning, the man saw June staring from the opposite apartment. With a chilling glare, he turned, and was gone. She instinctively knew he was coming to kill her because she had would be able to identify him as the murderer…