The Missouri attorney general’s office will investigate rising propane prices and a possible shortage of the gas. Attorney General Chris Koster says he has received many complaints of prices topping five dollars per gallon. Lawmakers are calling on Koster to investigate the issue to make sure companies aren’t price gouging. The Missouri propane gas association says the rising costs are caused by higher exports and increased domestic demand due to cold weather and low crop yields. Koster says his office is working with nine other Midwest states in its investigation.