Last week, news of a slow leak in the International Space Station raised concerns about astronaut safety, as well as admiration for their ingenuity in handling it. A repair with tape and sealant corrected the slow depressurization, and the fix remains in place and keeping cabin pressure steady. The assumption was that either a micrometeoroid or space debris struck the Soyuz craft where the hole was discovered, part of ongoing concerns over space-launch waste stuck in various orbits around the earth.

However, closer inspection suggests that the hole was drilled, which means it was either an engineering error or a deliberate attempt at sabotage, the Russian space agency now claims. And that means the six current inhabitants might become part of a whodunit worthy of Hercule Poirot:

But the incident’s fallout continued this week, after Russian officials who were subsequently tasked with examining the hole concluded that it had been drilled — potentially deliberately. Even the possibility of human interference could prove to be explosive, given that the ISS is one of the last remaining joint projects between Moscow and Washington. …

Investigators did not specify whether they believed the hole was drilled on Earth or in space, but Russia’s Roscosmos space agency did not exclude the possibility of sabotage.

“There were several attempts at drilling,” Roscosmos head Dmitry Rogozin was quoted as saying by Russian media outlets.

“We are checking the Earth version. But there is another version that we do not rule out: deliberate interference in space,” Rogozin said.

Currently, the crew consists of three Americans, two Russians, and a German astronaut, and the next departure date won’t arrive until December. It seems almost impossible to suspect that one of the six people whose lives depend on the structural integrity of the craft would have drilled a small hole into space. Why start a slow leak that would be surely discovered? If one was suicidal and wanted to put the others in danger, there are undoubtedly quicker and more reliable methods for achieving those ends.

Nor does sabotage on the ground seem likely, for similar reasons. In a manufacturing process with as many mission-critical elements as there are in space flight, putting a small hole in a module is almost certainly one of the lesser ways to induce a catastrophic failure. The capsule arrived three months ago, and the hole was small enough to avoid detection until last week.

Fortune has a better explanation, or at least a theory:

The Russians are overseeing the investigation—they built the module, after all—and, if they can identify the culprit, they say they will publicize their name.

The module was built by Russian company Energia, and a former employee told Russian media that technicians there have made similar mistakes in the past. On one occasion, a technician accidentally drilled through the hull of a re-entry module and tried to cover it up by sealing the hole with epoxy—he was found out, though, and sacked.

This seems far more likely to be the actual explanation, especially since there’s a history of similar errors. One has to wonder why Energia hasn’t adjusted its inspection regimes to account for such mistakes, but if this is what happened, the Russian government will likely insist on such an adjustment in the future. This looks like a good case in which to apply Hanlon’s Razor: Never attribute to malice that which is adequately explained by stupidity.

NASA has issued a statement of full confidence in Russia to complete their investigation and fix the problem. However, NASA and the Trump administration should seriously consider the implications of having to rely on Russia to get back and forth to the ISS. We need transport over which we can apply direct oversight and inspection, even if this just turns out to be a manufacturing fumble. It’s time to accelerate our efforts and develop an American option for manned space travel. Either we’re fully invested in a manned space program, or we need to stop pretending we are.