Researchers say that as few as three major criminal groups are responsible for smuggling African elephant ivory tusks.
A tusk represents a dead elephant.
And the research comes as Africa's elephant population is decreasing quickly.
The elephant population in Africa is estimated to be about 415,000.
In 1979, there were about 1.3 million elephants on the continent and 100 years ago, the number was 5 million.
The new study was published in Nature Human Behavior.
The researchers examined the DNA of elephant tusks and evidence including telephone, financial, automobile and shipping records.
They used the information to identify connections in trafficking operations across the continent.
Biologist Samuel Wasser of the University of Washington is a lead writer of the study.
He said he hopes it helps police target the leaders of these networks instead of the elephant killers themselves.
Criminal organizations can easily replace the low-level poachers.
"If you can stop the trade where the ivory is being consolidated and exported out of the country, those are really the key players," said Wasser.
Consolidate means to join or combine together into one thing.
Each year, an estimated 500 metric tons of poached elephant tusks are shipped from Africa, mostly to Asia.
For around twenty years, Wasser has been interested in a few key questions: "Where is most of the ivory being poached, who is moving it, and how many people are they?"
He works with wildlife officials in Kenya, Singapore, Malaysia and elsewhere, who contact him when they discover ivory shipments.
He flies to the countries to take small samples of tusks to study the DNA.
He has samples from the tusks of more than 4,300 elephants taken out of Africa from 1995 to the present.
Biologist Robert Pringle, who was not involved in the study, praised the work.
He said the data shows connections that can lead to "strong inferences."
In 2004, Wasser showed that DNA from elephant tusks and waste could be used to find an elephant's home location to within a few hundred kilometers.
In 2018, he recognized that finding identical DNA in tusks from two different ivory seizures meant they were taken from the same animal--and likely by the same poaching network.
The new research identifies DNA belonging to elephant parents and children, as well as brothers and sisters.
Such genetic links can provide information for wildlife officials seeking other evidence--cell phone records, license plates, shipping documents and financial statements--to link different ivory shipments.
John Brown III is a special agent with the United States Homeland Security Department and wrote the study with Wasser.
The agent's work on environmental crimes goes back 25 years.
Brown has told the Associated Press that in the past, a single seizure of illegal goods would rarely lead to the identification of the major crime group responsible.
But now, he said, "The DNA links can alert us to the connections between individual seizures."
The new research led to the discovery that only a very few criminal groups are behind most of the ivory trade in Africa.
Researchers identified several poaching hotspots, including areas of Tanzania, Kenya, Botswana, Gabon and Republic of Congo.
Tusks are often moved to storage centers where they are loaded into shipping containers with other illegal goods.
Then, the containers go to ports for travel out of Africa.
Traffickers that smuggle ivory also often deal in other illegal goods, as well, the research shows.
A fourth of large seizures of pangolin scales are mixed with ivory, for instance.
The pangolin, a large ant-eating mammal, is poached heavily.
Brian Arnold, a Princeton University biologist who was not involved in the research, said, "Confronting these networks is a great example of how genetics can be used for conservation purposes."
I'm John Russell. And I'm Ashley Thompson.