My 19yo daughter had a stalker at uni last year, first year, first term. Fellow student on the same course.
She was very clear that she isn’t interested romantically (not interested in men at all), but he wouldn’t leave her alone.
Unwanted gifts, emails, texts. He had her contact details because it started innocently as a friendship during a lab session, but quickly went way beyond in his eyes.
She talked to him several times and sent him a clear email before christmas, to leave her alone, the same day he turned up backstage at a concert she was playing in with red roses. It freaked her out.
I told her to get Student Support involved, they took it very seriously, helped her formulate an email which clearly said no contact and she would go to the police if he contacted her again.
After that, 2 months of nothing, then another email “please explain why you don’t like me...”
Student Support involved the police who went round to his student accommodation and talked to him.
Since then he’s backed off.
I am still worried as she is hundreds of miles away at uni, but she knows to call 999 if he ever stalks her at her flat again (police have said that), her flatmates know what he looks like and are aware.
Absolutely get her to involve the police, they will take it seriously.