(Jefferson City) The state is investigating after an unauthorized doctor signature was reportedly used to help about 600 Missouri patients get medical marijuana cards.

State Health Department spokesperson Lisa Cox says one doctor reportedly had their credentials stolen and used without their knowledge.

Cox had this to add.

Individuals impacted are being notified and given a deadline to submit a valid doctor’s approval to the state.

Missouri could start selling medical marijuana later this summer, possibly in August, to patients with qualifying health conditions.