PENDLETON, Ind. (WOWO) — Two rare tortoises stolen from the Indianapolis Zoo earlier this month were found alive and unharmed Tuesday afternoon according to Indiana State Police.

Around 4 p.m., park visitors walking near the museum spotted a cardboard box with a paper plate on top and a note referencing the zoo. Inside were the missing Egyptian tortoise and Northern Spider tortoise, both of which are critically endangered species.

Zoo staff later confirmed the animals’ identities by scanning their implanted microchips.

Indiana State Police Captain Ron Galaviz called the recovery “a bit of good news in a very unusual case.”

“One of the unique aspects of this is the fact that these particular species — the Egyptian tortoise and the Northern Spider tortoise — are currently listed as critically endangered,” Galaviz said. “Thanks to modern technology, we were able to locate and positively identify them using their microchips.”

Investigators are still working to determine who took the tortoises from the zoo and why.

“We’ve been asked, ‘Why would somebody steal two critically endangered tortoises?’” Galaviz said. “Maybe they wanted to keep them as personal pets or make a quick buck — I really can’t speak to that at this point.”

Galaviz added that multiple agencies are collaborating on the case, including Indiana Capitol Police, Pendleton Police, the FBI, and the U.S. Department of Agriculture Office of Inspector General.

“We’re working diligently to find out who’s responsible,” he said. “Hopefully we’ll be able to develop information that helps point us in the right direction. Right now, the good news is that the tortoises were found safe.”

As for possible charges, Galaviz said that decision will depend on the outcome of the investigation.

“Ultimately, it’ll be up to the prosecutor to determine whether this results in state or federal charges,” he said. “It could be more than one, but I don’t want to speculate just yet.”

No suspects have been named at this time. The investigation remains ongoing