Correction: An earlier version of this story contained incorrect information about the amount of fentanyl pills seized. The actual number of pills seized is over 500K and the error has been corrected. We apologize for the error.

CASA GRANDE, Ariz. (KLAS) — Two women were arrested and over 500,000 fentanyl pills were seized on Monday after a traffic stop.

31-year-old Martha Lopez and 30-year-old Tania Luna Solis were stopped near Casa Grande, about 50 miles from Phoenix. They were stopped for speeding in an SUV that Lopez was driving, according to police.

Police said that two juvenile passengers were also in the car.

During the stop, officers discovered around 500,000 pills concealed in collagen supplement bottles, alongside a gun and a “large amount of U.S. currency,” police said.

Both women were booked on charges including possession, transportation, and importation of narcotic drugs for sale and child endangerment.

K9 Deutz, who was recently bitten by a rattlesnake and returned to service, helped discover the illicit pills.

K9 Deutz helped Casa Grande police find over 500,000 fentanyl pills during a traffic stop. (Courtesy: Casa Grande police)

“The transport and sale of drugs in our community affects us all. It is hard to quantify the number of lives this investigation has saved, but I am sure we are making a difference. Our Officers are combating this issue daily and I commend their efforts, especially knowing our K9 who was recently bitten by a rattlesnake is already back in full service,” said Casa Grande Police Chief Mark McCrory.