I looked it up, it was an ice pick. I'm sure I was just remembering The Woman in the Window with the scissors thing.
Thanks. My memory was short-circuiting. Hmmm, a lot of murder movies with an ice pick or scissors (though they rarely look like killing blows.) I know because of the time period, but I still unconsciously look for blood and wonder why there are not holes in the clothing (for a few seconds ).