Sexual Harassment is Never Okay!

In an office job that I had a number of years ago, there was a really attractive woman that worked as the firm receptionist, Laura. She was in her mid-30s and had been working with us for about seven years. She was well-regarded by her colleagues and superiors for her expertise and creativity. However, over the past few months, her work environment has taken a dark turn due to the actions of one of our co-workers, Bill. Bill has been with the firm for over twenty years and has always made unwelcome advances and inappropriate comments towards her. It started subtly, with occasional compliments on her appearance that made her uncomfortable. But as time went on, Bill's behavior escalated, and he began touching her inappropriately, even going so far as to send explicit messages on our firm email. Feeling humiliated and distressed by Bill's actions, Laura confided in a few of us about the harassment. I tried to be empathetic and supportive, but I had also seen Bill's actions firsthand. I noticed slowly that Laura isn't wanting to hang out with us at lunch, almost as if she was embarrassed by what was happening. I chose to be the one that said something to Bill, and I asked him to stop making her feel so uncomfortable. I told him it was creating an unpleasant work environment for all of us in the office. Instead of taking me seriously, he kinda laughed and said, "You know I think all of you ladies are Hot". I wasn't looking for a compliment and told him that he was now making me feel uncomfortable. As time progressed, Laura found it tough to concentrate on her work, so she chose to resign. He didn't just create a hostile work environment for Laura, but for all of us and HR refused to acknowledge that it was a problem because he had been with the firm for so long and was a producer of a lot of new business. They claimed there was insufficient evidence to support any of our allegations, and some senior managers seemed reluctant to address the issue, fearing it would tarnish the company's reputation. My question is, when will this stop?!