Before Hiring a Manager: Do The Waiter Test
Anyone considering hiring a manager or somebody to perform a leader role should be put the person through the Waiter Test.

You invite the person you consider hiring out to a restaurant and see how he behaves to the waiter.

Everybody is good at dealing with their peers or superiors, but the important thing is how a person deals with his subordinates.

The bad sign is if he or she changes behavior to the worse. If so remove the person from your potential hiring list.