What's up with the Capitol Jail?

In this thread Can We Get Zombi John Banner to Be Atty General?, Captain Carrot mentions that the congressional sergeant-at-arms has the power to place wrongdoers in custody at something called the capitol jail.
Google is not helpful in expanding on that beyond some claims that there used to be cells in the basement of congress, and perhaps at the supreme court. Their is a jail called D.C. Capitol Jail at 1901 D Street in Washington, where at least one person convicted of “Disruption of Congress” was housed recently. Is that where Meirs would end up, or is there another facility? What’s the history of the place? How many people has congress imprisoned for offenses against its dignity etc.?

The jail at 1901 D Street Southwest is just the DC city jail. In the past, when people have been jailed for contempt of congress, that’s where they went. There’s not a special Capitol jail.

There was some discussion of housing offenders in the office of Sen. Ted Stevens (R-Alaska) and subjecting them to his explanation of the Internet “tubes,” but Eighth Amendment concerns put the kibosh on that.

To the dungeon with them!

Parliament House in Canberra - a modern building - has several cells in its bowels (I believe they have never been used). I’m pretty sure the Houses of Parliament in London have them too.

Cells or cellars? Does your parliament ritualistically search them for gunpowder like the British do for the State Opening of Parliament?

I used to live a stone’s throw from the headquarters of the Capitol Police, which is probably four blocks or so from the Capitol itself, and pretty much across the street from one of the Senate office buildings. I can only assume there was some kind of holding tank there, but I frequently read in the local papers that real troublemakers arrested by the Capitol Police are moved to the DC jail.