Have a leak in wall and want to know who to call out

[Gerard Leeson]

Was looking for advise on who to call on a leak that is appearing on a basement ceiling along the wall. The building is a two story brick multi-unit. I am not at the building and the manager is unable to tell if it's a pipe, tuck pointing or other cause. Sounds like a small but constant drip. It has been raining but no one has noticed when it started. Who would best be able to figure out the origin of the problem? Know this may be a ridiculous question but want to get it resolved quickly without calling out a million people. Thanks in advance.