My dad was there. He was a combat engineer and they were at the "sharp end" - he actually knew the partisani who caught Mussolini. He said it was an ESSO station in the middle of Milan - they hung up his body, that of his mistress Clara Petacci, and 2-3 other people.
We have dad's photos of the partisani (waving from the back of an ox-cart, sitting around drinking wine) - he took a bunch of photos of Mussolini & Co. but we can't find the negatives. >-<