a line on (someone or something)
Helpful information about how to find, contact, or reach someone or something. John says he can get a line on a guy who can fix the car for half the price. Sally has a line on a job opportunity in New York that you should look into after you move.
*line on someone or something
Fig. an idea on how to locate someone or something; an idea for finding someone who can help with someone or something. (*Typically: get ~; have ~; give someone ~.) I got a line on a book that might help explain what you want to know. Sally has a line on someone who could help you fix up your apartment.