This situation happened months ago in my company:
One female intern came to me, she was almost crying, telling she wanted to quit. She was about to tell me what happened but I only wanted to hear her only after she was a bit calmer. I told her to take the day off, since she had a son, she could use the day to do something more fun. At this point I thought that maybe it was some sort of problem with a phone call. She worked primarily answering calls and giving initial support to users.
After a quick investigation: some employees had a whatsapp group for sharing reddit links, gossip. She asked for an invite and was in the group only as a reader, months later she never reads the group messages and didn't realize the group now became a porn-heaven. Three engineers forgot that she was there made some vulgar comments about her, she discovered. After she confronted them they did some nasty sexual comments about her being in a porn-only whatsapp group.
The three nasty commentators were fired on the spot. Engineers often think code and their github account the is exclusive reason I'm hiring them. They argued about how that was their private, personal activity outside office hours, digging their hole deeper.
After firing them I had a private talk with every engineer and explained what happened and talked about the event. The reason I did this was to find another employees with the same mindset as the ones who were fired, and I did. They were fired weeks after.
One of the three nasty engineers was a woman, when confronted it was clear to me that she was either a sexist or some sort of misogynist.