A ton of news today. But don’t miss this. A great look at Marco Rubio rushing to quell the right-wing backlash/rumor mill on the immigration bill. He’s even putting up a new website.

TPM reporter in building reports Boston Federal Courthouse was being evacuated at approximately 3 PM this afternoon.

As you can see, over the last 10 to 20 minutes there have been multiple conflicting reports about whether a suspect has been identified, placed in custody or been arrested in the Boston marathon bombings. Our current feature story says a suspect is in custody. We are currently following the Associated Press and the Boston Globe, both of which – apparently independently and based on their own sources – are reporting that a suspect is in custody. Meanwhile, on the air, CNN now appears to be backing off their reports of an arrest or a suspect in custody. NBC continues to say, no one in custody. There’s some confusion, perhaps a semantic distinction, between being under arrest and in custody – not precisely the same thing. I suspect that in a very short while, the confusion will resolve itself. But this is the terrain of conflicting accounts as of 2:40 PM.

For now, we’re following the AP and the Globe.

Late Update: The AP now says the feds are denying a suspect is in custody.

Welcome to the brave new (kind of neat and also chilling) world of real-time chat forum amateur bombing investigators.

Rapidly breaking news.

Over the last 15 minutes, CNN has reported that investigators report “substantial progress” in the investigation of the Boston bombing probe. Additionally, CNN’s John King, on the basis of unnamed law enforcement sources, says investigators believe they have identified a suspect from videotape evidence.

More as we hear it.

We’ve got a number of overlapping stories breaking out or in motion at the moment. There are two letters — one to Sen. Wicker and another to President Obama — that are believed to have been contaminated with the poison ricin. In addition there are two ‘suspicious package’ situations currently in progress on Capitol Hill.

I would emphasize that neither of these letters got to within any physical proximity of their intended recipients. And there is still on-going testing to confirm definitively that it is in fact ricin.

With the suspicious package situations, remember quite often these suspicious package situations turn out to be false alarms. For the moment we’re waiting to hear more.

We’re publishing running updates on each of these stories here.

Late Update 12:49 PM: CNN’s Dana Bash is reporting that Capitol Police are now saying that the suspicious packages have been removed from the buildings and that the buildings are now open again for business. The statement was less clear on whether there’s been a determination about what the ‘suspicious packages’ were.

So remember the disgraced former Justice of the Peace who’s now the ‘prime suspect’ in the killings of those Texas DAs? Well, now his wife has been arrested and charged with capital murder.

Mark Sanford got a rude awakening last night on the Appalachian Trail back to the House of Representatives. His now ex-wife has accused him of trespassing and she’s taking him to court.

Fox pulls an episode of “Family Guy” that came out before Monday’s bombing but which involves joking reference to a character mowing down Boston marathon runners with his car.

Benjy Sarlin has the definitive explainer on how the path to citizenship would work under the proposed Senate plan.