Even apart from allegedly setting the bombs that killed three people at the Boston Marathon and injured many others, shooting and killing a police officer, and engaging in a pitched battle with law enforcement, Dzhokhar and Tamerlan Tsarnaev may have been criminals. Massachusetts has some of the toughest gun laws in the nation; the Tsarnaev brothers apparently broke them.

At nineteen years old, Dzhokhar Tsarnaev wasn’t old enough to legally own most guns. Tamerlan Tsarnaev, at twenty-six, was, but he reportedly didn’t hold the permit that Massachusetts requires of gun owners. But according to published reports, there were at least four on the scene in Watertown: an M4 carbine rifle, which is, the Times notes, “similar to ones used by American forces in Afghanistan,” along with two handguns and a BB gun (the only one that Dzhokhar could have legally owned). If nothing else, these facts ensure that the Tsarnaevs’ names won’t just come up in relation to the discussion about immigration reform that is taking place in Washington right now, but in the ongoing debate about gun control as well.

Some on the right have already begun arguing that the fact that the Tsarnaevs apparently owned their guns illegally is evidence that gun laws simply don’t work. “Since they didn’t obey the laws already on the books, maybe more laws for them to ignore would have helped,” Doug Powers wrote for Michelle Malkin’s Web site. “Maybe a separate law with slightly different wording that had ‘seriously, pay attention to this one - we’re not kidding’ written in bold would have gotten their attention.” Many other conservative bloggers have expressed similar sentiments over the past day.

Similarly, for supporters of gun control, it is a simple matter to ask if tighter laws, like those the Senate rejected last week, might stop people like the Tsarnaev brothers from buying guns in the future.

The problem is that we don’t yet know how the Tsarnaevs got their guns. (The feds are reportedly working on tracing the weapons now.) Maybe the Tsarnaevs bought their guns on the street; maybe no gun-control law would have stopped them from getting what they wanted. Maybe they had a friend, or friends, who got the weapons for them. (The only people charged in the Columbine High School shooting, since perpetrators Eric Harris and Dylan Klebold killed themselves, were two men who helped Harris and Klebold obtain the guns they used in the massacre.)

They might have purchased the weapons at a gun show, though, or they could have gotten them online, from a Web site like Armslist, which, as a recent Times report showed, has made it easier for people who are prohibited from owning guns to avoid the background checks they would be unable to pass. And if the weapons were purchased in another state, it will be another bit of evidence that gun-control supporters can use to suggest that the reason the laws in places like Massachusetts don’t work the way they should isn’t because they’re fatally flawed but because lax restrictions in other states make them difficult to enforce, and a national standard is the only way to truly make a difference. If the M4 proves to have the sorts of modifications that would mean it falls under Massachusetts’s assault-weapons ban, or that it would have been prohibited under the assault-weapon ban that recently died in the Senate, that will raise other questions, too.

Until we know exactly how the brothers got their weapons, this is just fairly empty speculation. But we will presumably have some answers soon, and once we do, both sides will have more stories to tell about guns. Whether any of them would make a difference in this Congress is another matter.

Photograph, of investigators in Watertown, Massachusetts, by Matt Rourke/AP.

Read more of our coverage of the recent events in the Boston area.