By the time Boston Police arrived at 216 Tremont Street, the suspects were gone. The block was sealed off between Boylston and Stuart streets. Evidence markers lay across the sidewalk, several of them on articles of clothing.

Three victims. Three gunshot wounds. Two of the men got themselves to Tufts Medical Center. The third went by ambulance. All three are expected to survive.

What is not known, as of Tuesday morning: who pulled the trigger, what the dispute was about, and how the three suspects walked out of one of Boston's most-trafficked entertainment corridors without a single arrest. The block sits a short walk from the Wang Theatre, the Boch Center Shubert, and the Tufts Medical Center campus.

The Boston Police statement was short and pointed: "The people involved may be familiar with one another." Translation, by way of long police-blotter shorthand: this was not random. Someone outside The Tam on Monday night knew the men who got shot, and knew the men who did the shooting.

That detail is meant to calm the public — it is also the detail that has triggered Tremont Street's small-business community throughout the week. The Theater District has spent the past two years trying to recover from a series of high-profile incidents downstream of Boston's pandemic-era nightlife collapse. A triple shooting on the sidewalk outside one of its most recognizable bars, in front of a Buffalo Wild Wings, two blocks from the MBTA Boylston station, is not the rebuilding story the neighborhood has been pitching.

The Tam, at 222 Tremont Street and now operating from 216, has been a fixture of the Theater District since the 1970s. It is the kind of dive Boston actually misses when it loses — a thin-front, cash-and-card-friendly room with a stage in the back and a clientele that runs from regulars to first-time tourists walking off Boston Common.

It is also one of the last bars in the Theater District that stays open late on a Monday.

Boston Police have not, as of Tuesday morning, named the suspects, the victims, the charges they would face if caught, or even how many gunmen were involved. The department's tip line for the case is 617-343-4571.

The investigation, BPD said, is "active and ongoing."

This is a developing story.