Opinion by Editorial Board March 6, 2021 at 8:00 a.m. CST MORE THAN a year after the coronavirus pandemic began, its origins are mysterious. The truth may take years to discover, but now is a good time to relaunch the search for it. A joint inquiry by the World Health Organization and China has run into trouble, as a group of 26 scientists pointed out this week in an open letter to the WHO. Both the possibility of a zoonotic spillover from animal hosts and that of a laboratory accident need independent, expert investigation -- and it is time for a new team to seriously tackle the laboratory hypothesis. Why is the issue of the virus origins so important? Because the source and method by which the virus made the leapto people are critical to prepare for any future pandemic. Too much political heat has already been spent on this issue, some generated by China, where the first major outbreak began, and some by Donald Trump in his attempt todistract attention from his catastrophic pandemic response as president. The blame-throwing must not impedefinding the truth. The WHO-China investigation team, focused on zoonotic spillover, is writing a report, which the director general ofthe WHO, Tedros Adhanom Ghebreyesus, says will be released the week of March 15.ADAnother hypothesis, that the pandemic was ignited by some kind of laboratory leak or accident, is denied by China. However, a senior researcher at the Wuhan Institute of Virology, Shi Zhengli, was working on "gain of function" experiments, which involve modifying viral genomes to give them new properties, including the ability to infect lung cells of laboratory mice that had been genetically modified to respond as human respiratory cells would. She was working with bat coronaviruses that were genetically very similar to the one that caused the pandemic. Could aworker have gotten infected or inadvertent leakage have touched off the outbreak in Wuhan? The joint WHO-China team said in its Feb. 9 news conference in Wuhan that the laboratory hypothesis was "extremely unlikely" and would not be further studied; later, Dr. Tedros said that nothing was off the table. As the26 scientists point out in their letter, the team lacked the training and forensic skills required to investigate this possibility. They were under strong pressure from China to steer clear of the subject altogether.What's needed is an independent, multidisciplinary and unfettered investigation into the origins of the outbreak, both the zoonotic and laboratory hypotheses. China's obduracy is not going away. The WHO, a membershiporganization, lacks the powers to pry open closed doors in China, and there is not another good alternative. However, Dr. Tedros could appoint a new team of highly qualified international experts, including forensicspecialists, to investigate the laboratory-leak hypothesis, and forcefully insist that China not stand in its way. If heopenly challenged China on this matter, he would have the support of a world wanting to know how this nightmarebegan and how to prevent another.