Authorities believe two women arrested last week in St. Charles may be part of a ring that resells stolen baby formula.

The two St. Louis women were stopped Thursday after an officer recognized their car as one used in the theft of formula from a St. Charles Wal-Mart store.

Officers say they found 40 cans of Enfamil valued at $619 in the car, along with two large purses they believe were used to conceal the formula during the theft.

Police say both women told officers they had made multiple trips to the store on Thursday and four other days. Investigators are trying to determine who was purchasing the stolen formula.

Both women were arrested on suspicion of felony theft.