Scientists hoping to protect endangered orcas might have inadvertently killed one instead. A killer whale tagged by NOAA researchers in Washington state in February turned up dead in British Columbia five weeks later, reports the CBC.

On Wednesday, US researchers released a report suggesting the 20-year-old whale, known as L95, died of a fungal infection linked to a tracking dart, reports CTV News.

The theory: After researchers missed their first shot from an air rifle while battling high winds and waves, the dart was recovered from the water and fired again, without proper sterilization.

More from Newser:

This time, it landed. “This is to my knowledge the first case where it appears the tag deployment was a contributing factor to the death of an animal,” says the head of Canada’s Department of Fisheries and Oceans.

Researchers say it's possible the whale had some other illness that played a role, but the NOAA has suspended its tagging of orcas. One big question to be answered, as posed by National Geographic: "Does a common tool intrinsic to marine research around the globe—satellite tagging—pose more risks to large marine mammals than once thought?" Scientists had been hoping to track the orcas' location in winter to better understand the population's decline.

With L95's death, just 82 southern resident orcas remain. (This killer whale has been swimming since the days of the Titanic.)

This article originally appeared on Newser: Scientists Might've Accidentally Killed an Endangered Orca