JIM SUHR, AP Business Writer

ST. LOUIS (AP) — Missouri’s attorney general is taking Walgreen Co. back to court, alleging the nation’s biggest pharmacy chain is violating a settlement reached last year over its pricing practices.

Attorney General Chris Koster’s office asked a judge Tuesday to hold Walgreen in contempt for violating terms of the 2014 deal.

Koster sued Walgreen in 2013, accusing the retailer of overcharging customers and using deceptive advertising and pricing schemes in Missouri. Koster says the investigation began after consumers complained that display prices didn’t match up with what they paid at checkout.

But Koster alleges Walgreen violated the settlement by not removing expired sales tags from shelves, and deceiving customers about those products’ prices, in roughly 1,300 recent instances.

Walgreen said it may publicly comment later Tuesday. The company is based in the Chicago suburb of Deerfield, Illinois.