Authorities in Alabama are now offering a combined $100,000 reward Monday for information surrounding a mass shooting in Birmingham over the weekend that left four dead and at least 17 others injured.

Here's what we know so far.Where did the shooting happen? It happened in Birmingham Five Points South, which is an entertainment district with restaurants and nightlife. How many people were shot?Birmingham police said four people are dead and four others have life-threatening injures.

Law enforcement officials were working to track down the shooters who killed four and injured at least 17 others in a popular area for nightlife.