Customs agents confiscate thousands of fake Louboutin shoes.
The other shoe dropped this week for a counterfeit operation involving about 20,000 pairs of Christian Louboutin knock-offs when the shoes were seized at the Los Angeles-Long Beach seaport.
Authorities seized five shipments -- the latest arrived Tuesday -- from China.
Estimated value of the red-soled fakes -- $57,490.
Among the reasons authorities suspected the shoes were not genuine -- some pairs had different shades of red on the soles.
"If you were going to buy an original pair of the shoes, you wouldn't have a different shade of red on the sole," said Guillermina Escobar, of Customers and Border Proection.
They are likely to be destroyed.
The 20,457 pairs have an estimated retail value of $18 million, according to U.S. Customs and Border Protection.
The first shoe shipment was discovered in July.
Four more shipments were found this week.
"The first tip-off was that the shoes were coming out of China, but again they were manifested just as footwear," said Todd Owen, Customs and Border Protection director of field operations. "So the officers had to take a close look and then the import specialist had to take a look at how the different soles were made."
The shoes would likely be sold swap meets, private parties or online, CBP agents said.
In 2011, there were 1,020 trade seizures at the port with a value exceeding $37 million -- an 18-percent increase in the number of seizures in 2010.