Does the tone of your colleague sound ‘weird’?
It’s easy for a hacker to collect email addresses and names of someone’s colleagues, so bear in mind how people usually write. If you receive a message from your manager with a header that doesn’t sound like her, chances are it’s not from her. A good way is to look whether the person refers to a document that is attached in the e-mail. Also, check that the Atlas Copco signature in the footer of the email looks correct