Should I tell on a colleague who I think is faking a back problem?

Work ethics is a fortnightly feature in Guardian Work where a reader submits a workplace dilemma and asks for your help. A selection of the best answers will appear in Saturday's paper. (And if you have an office dilemma you'd like to share with our readers, please email us ). This week's question A guy in my team has taken lots of sick days recently, claiming he has a back problem. However, a friend swears she saw him cycling through the park the other day when he was supposed to be at work! Should I dob him in to our boss? His absence always causes loads of extra work for the rest of us. What are your thoughts?