Despite how easy they make it look on TV dramas, determining time of death for a body requires a lot of difficult guesswork (unless someone is there when the person passes, of course). A range of environmental factors and other mitigating circumstances make any declaration of time of death an estimation at best. But a team of Italian scientists think they’ve found a built-in clock in the human nasal cavity that ticks off the minutes after a body expires, and it could make estimating the time of death a more precise exercise.

There are several ways for forensic examiners to roughly gauge time of death–decomposition rate, the state of rigor mortis, body temperature–but the specific circumstances of death can often influence those indicators, introducing variables that are difficult to account for.

But researchers at the University of Bari in Italy theorized that nasal cilia–small finger-like projections in the nose that help direct mucous, bacteria, and dust out of the nose–continue to pulsate after death. To test their hypothesis, the team took samples from 100 recently deceased cadavers to examine the characteristics of the cilia postmortem.

They found that the cilia do indeed continue beating up to 20 hours after death and that the beating slows at a predictable and consistent rate during that time, regardless of environmental factors. That means forensics teams and doctors could use the rate at which a person’s cilia are beating to make determining the time of death less of an art, and more of a science.

New Scientist