It’s a bad time to be a murderer.

Which is a good thing, I think almost all of us would agree.

Some defense lawyers, though, are leery of certain techniques that can lead police to suspects who, as recently as two decades or so ago, might never have aroused the slightest suspicion from investigators.

I am, as you might well have surmised if you have more than a passing interest in criminal matters, referring to DNA.

Employing this genetic “fingerprint,” which is unique to every human except identical twins and is contained within our bodily fluids, hair and skin cells, to find killers is hardly a new tactic, of course.

Indeed the process dates back near four decades, to a pair of murders in England.

I recommend Joseph Wambaugh’s book on the 1986 case, “The Blooding,” for a thorough examination.

In what might be termed the early era of DNA detection, detectives from the 1980s through the early 2010s typically used the technology to bolster their case against a suspect they had already identified through conventional means such as an eyewitness report, a gun or ammunition match or an actual (not a DNA) fingerprint.

But the immense growth in DNA databases — and in particular ones compiled by genealogical companies — has paved a wholly different investigatory avenue.

It’s known as IGG — investigative genetic genealogy — and its potential to catch murderers is considerable.

The limitation with DNA is that even if detectives collect a solid genetic profile from evidence at a crime scene, that profile is worthless if there’s no way to pinpoint suspects against whom to compare the profile.

And until relatively recently, it was impossible to conduct anything like a thorough search for that potential match.

The DNA profile was in effect a needle against the quite imposing haystack of humanity.

But the proliferation of DNA profiles, again thanks largely to the aforementioned databases of genetic information willingly submitted by people who want to know if their ancestors actually came from Hungary as grandpa always insisted, has wrought dramatic changes.

(Two of the leaders in the genealogical business, Ancestry.com and 23andMe, do not cooperate with police.)

At the simplest level — not that DNA is truly simple, of course — IGG allows police to potentially find suspects by an indirect, but scientifically unimpeachable, process.

Here’s how it works:

Police compare a DNA profile from a crime scene to public databases whose customers have agreed to make their profiles available. Detectives don’t expect to find an actual match — the odds are quite slight even with the burgeoning number of profiles.

Rather, investigators hope to find profiles from a suspect’s relatives. This needn’t be a close relative. Distant cousins can be sufficient to help police assemble a family tree by which they can either eliminate a suspect or, ideally, confirm their suspicions about who’s guilty.

The most prominent case solved through this method is that of Joseph James DeAngelo, the California man known as the Golden State Killer.

Police had a DNA profile of the serial murderer and rapist from crime scenes in the 1970s and 1980s.

The investigation, which involved a private DNA researcher as well as police, resulted in a roster of relatives of the still unknown suspect, and eventually a list of potential matches to the suspect’s profile. Police narrowed that list to DeAngelo. They obtained a DNA sample from a tissue in his trash, and it was a match for the profile from the crime scenes.

Police arrested DeAngelo in 2018. He pleaded guilty to 13 counts of first-degree murder in 2020 and was sentenced to life in prison without parole.

More recently — and potentially more interesting from a legal standpoint — genetic sleuthing is involved in the highly publicized murder of four University of Idaho students in their Moscow apartment in November 2022.

Bryan Kohberger is charged with stabbing Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin.

Idaho police said they identified Kohberger as a suspect based on surveillance camera video that showed his car repeatedly driving near the victims’ apartment, as well as data from his cellphone.

But police also got a DNA profile from a leather knife sheath they found beneath one of the students.

Unlike in the DeAngelo case, police had enough non-DNA evidence to arrest Kohberger.

And, once they arrested him in December 2022 in Pennsylvania, they could, without violating his constitutional rights to illegal search and seizure, obtain a DNA sample from him to compare to the profile from the sheath.

That DNA evidence, along with the circumstantial evidence from cameras and cellphone records, makes up the heart of the case for Kohberger’s guilt.

But his attorneys have also raised potential constitutional issues related to the IGG process that Idaho investigators also used, even though the prosecution apparently won’t be introducing that evidence at Kohberger’s trial.

Investigators used a DNA profile they obtained from trash outside Kohberger’s family’s home — another procedure that passes constitutional muster — to link the profile, through IGG, to the biological father of the person who left the DNA on the sheath at the murder scene.

The obvious implication is that the DNA from the trash was left by Kohberger’s father, hardly a surprise since the trash came from the family’s home.

It’s another potential genetic link connecting Kohberger to the murder, although not nearly so compelling as the direct comparison with Kohberger’s own DNA.

Yet even though IGG likely won’t be an issue in the Moscow murders, I think it’s all but inevitable that the question raised by Kohberger’s attorneys — whether the technique could violate a suspect’s constitutional rights — will factor in future criminal prosecutions.

I respect the diligence of attorneys in protecting their clients’ rights — including clients who, like DeAngelo, are guilty of heinous crimes.

But I hope the judges who will ultimately decide on such matters — potentially including the U.S. Supreme Court — will recognize that investigators have not only a constitutionally valid right, but indeed an obligation to the public they are sworn to protect, to employ all scientifically valid tactics to catch and convict killers.

One of those tactics is comparing DNA profiles from people who voluntarily made their genetic information available for perusal, as in DeAngelo’s case.

I think that option is not only constitutionally sound, but frankly exciting.

It can only redound to society’s benefit when murderers can be betrayed not only by their own mistakes but by their own genes.