Apparently, there were no men present when the murder took place. There might have been some males, but no men.
Unless later reports contradict, it seems nobody tried to stop him.
Yes, I am jumping to conclusions. It might be the only exercise I get today.
Acording to the article, police arrived within two minutes of someone calling 911. The girl was most likely dead by the time the witnesses even processed what was going on and got themselves together enough to call 911.
Other than people trained to deal with violent situations (cops, military) the vast majority of people freeze up in a situation like this. Having just witnessed a bloody murder, few people are going to have the capacity to confront a deranged, blood-soaked lunatic.