An incident in which thieves stole more than $40,000 worth of insects and lizards from the Philadelphia Insectarium and Butterfly Pavilion last Wednesday is suspected to be an inside job, police announced Thursday.

The Philadelphia Police Department announced Thursday that officers believe three current or former employees of the insectarium may be responsible for stealing approximately 7,000 animals and rare insects, which make up 80 to 90 percent of the insectarium, on August 22 and on other days of the week.

Police say they have not yet made any arrests in the case, but authorities have been in contact with the suspects and have conducted a search of their homes to find surviving insects — and the records containing logs to keep track of them.

“They are extremely easy to hide,” Dr. John Cambridge, the insectarium’s director, told the New York Times Thursday. “We want to make sure that these creatures are treated with respect.”

“I really don’t think the perpetrators realize the severity of what they were doing,” he added. “We believe these were taken for the purpose of resale.”

Police were able to recover a handful of the missing insects and a Mexican fireleg tarantula, but a rare breed of venomous spider — the six-eyed sand spider — remains at large.

The insectarium, which opened in February 2017, announced it would be closing two floors of the building until November because of the theft and started a GoFundMe page Wednesday to replace some of the lost insects.