Ishitani told KABC that customers complained of getting bumps and rashes from products bought in Santee Alley.
He tweeted a picture of the counterfeit goods saying: "The best price is not always the best deal!"
Reina also disclosed in the tweet that bacteria and human waste were found in the counterfeit makeup products.
According to ABC 7, the LAPD raided 21 different locations in the Fashion District in downtown L.A. They had fake products from Kylie Cosmetics, Urban Decay, NARS, MAC and others.
Police in Los Angeles have confiscated around £500,000 worth of counterfeit make-up that was found to contain traces of risky bacteria, animal faeces, and - most worryingly - human urine and faeces.
The packaging for the fake products is nearly identical to the real deal, so it's hard to tell if a product is a unsafe counterfeit or it is the real deal.More news: 'The Walking Dead' Stars Break Down Season Finale Shocker
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Detective Rick Ishitani told ABC7: "They came back positive with a high level of bacteria and animal faeces". The products were tracked to the Fashion District, where officers did undercover buys.
Officials arrested six people and the suspects will face charges of trademark violations of major brands.
"Those feces will just basically somehow get mixed into the product they're manufacturing in their garage or in their bathroom - wherever they're manufacturing this stuff", Ishitani continued.
A lot of the products were very convincingly packaged, but at a hugely reduced price and - crucially - contaminated with human poo and wee.
"Quite a few of my friends own pieces of fake makeup - especially the Kylie lip kits - knowing that it's fake".