A 60-year-old woman who said she was travelling from California to Seguin was being investigated for drug possession.
Police initially stopped the woman's car on Graytown Road near I-10 because it did not have front or rear license plates.
After questioning the woman, police said they asked the woman for permission to search her car. Inside, they found six pounds of marijuana.
Police said the woman claimed she was in the medicinal marijuana business and showed some paperwork, but police said they were taking her in for questioning.
She may face drug possession charges.