Postal employees in Middlesex County knew something was wrong when they spotted millipedes and scorpions crawling around a mail truck and inside a post office three summers ago.

The critters were the work of Wlodzimie Lapkiewicz, a Metuchen man arrested Thursday on federal charges, officials said.

Lapkiewicz, 29, is accused of smuggling several species of wildlife into the country, including some that are endangered, between July 2015 and July 2018, the U.S. Attorney's Office in New Jersey alleged. He's charged with wildlife smuggling and false labeling of wildlife.

He's accused of shipping them to New Jersey from places like Tanzania, and falsely labeling the packages to avoid detection. He recently labeled one box containing multiple live, giant millipedes: "Plush Toys for my Friends Child about to be born," the complaint against him says.

Two species of scorpions that Lapkiewicz received, emperor and dictator scorpions, are protected under the Convention on International Trade in Endangered Species.

Authorities say Lapkiewicz was twice warned about his actions, and federal investigators eventually learned he was selling the creatures through his Facebook page.

Hello Everyone, I know quite few of you been asking and here they are. I'm offering about 30 or so Giant African... Posted by Wlodek Lapkiewicz on Saturday, April 7, 2018

Postal inspectors first learned of the imports in July 2015 when live scorpions and millipedes escaped from a package that originated from Tanzania in east Africa while on a truck that was on its way to Lapkiewicz's home.

A postal inspector interviewed Lapkiewicz that month, and he admitted ordering 20 emperor scorpions, 20 giant African millipedes, and five egg cases containing praying mantises.

The inspector told Lapkiewicz that it was unlawful to import live species via mail and gave Lapkiewicz a warning because he told the inspector they were for personal use, the criminal complaint against him says.

A similar incident occurred two months later, in September 2015, when two more millipedes were found on the loose in the post office.

Meanwhile, in France, customs officers seized two more packages addressed to Lapkiewicz, one containing 69 millipedes and one with 46 live emperor scorpions. They originated in Cameroon.

In December 2015, the U.S. Fish and Wildlife Service met with Lapkiewicz and they told him it was illegal to import invertebrates without obtaining the necessary authorizations. They filed no charges and told him to stop, the complaint says.

Federal investigators kept on him and found several individuals who purchased invertebrates or insects from Lapkiewicz, the complaint says. And he kept importing insects.

On June 20, customs officers in Indianapolis intercepted a Federal Express package addressed to Lapkiewicz containing live giant millipedes. And on July 3, fish and wildlife agents at John F. Kennedy International Airport in New York intercepted a package with 245 small containers with live orchid mantids inside.

Lapkiewicz is on Facebook under the name Wlodek Lapkiewicz.

That's also how he's listed on several web pages and past stories at the Philadelphia Insectarium and Butterfly Pavilion, where he was the living colonies director.

John Cambridge, the insectarium's CEO, said Friday that Lapkiewicz is no longer with the museum and he left a few years ago, amicably.

He knows him well - their relationship goes back to Rutgers University, where they both studied - and Cambridge described Lapkiewicz as one of the best breeders of that type of species.

"He was absolutely fantastic," Cambridge said.

A stunned Cambridge said the Philadelphia Insectarium has all its permits, and has a solid working relationship with federal wildlife authorities, and while the allegations against his former colleague have nothing to do with their organization, he said he could vouch for Lapkiewicz's work.

"I hope this is all just a giant misunderstanding," Cambridge said.

Lapkiewicz could face up to 20 years in prison and a $250,000 fine for the wildlife smuggling charge. The false labeling of wildlife charge carries a maximum penalty of five years in prison and a $250,000 fine.

After a court appearance Thursday, in federal court in Newark, Lapkiewicz was released on $50,000 bond.

Editor's Note: This story was update on Friday, Aug. 17, 2018 with comment from the Philadelphia Insectarium and Butterfly Pavilion.

Gianluca D'Elia may be reached at gdelia@njadvancemedia.com. Follow him on Twitter @gianluca_delia. Find NJ.com on Facebook.