HCC will soon update public on shooting threat. Here's what we know -- and don't know.

Houston Community College's Central Campus remains closed Tuesday as the college continues to investigate a shooting threat posted on social media over the weekend. Operations were also closed Monday on the Midtown campus as HCC police inspected campus facilities, enacted new security measures and tried to identify the person who made the threat. Here's what we know — and don't know — about the investigation, which is now in its fourth day.