Repair wall and find the leak

There appears to be a leak in our coat closet. I'm not sure if it's an old leak or a new one, but I need to find someone who can repair the closet walls and figure out if/where the leak is coming from. I'm unsure if I need a contractor or a handyman who knows what they are doing. I'm looking for recommendations for contractors or handyman/woman who are qualified and experienced with this type of work. Any recommendations?

Thank you.