ST. LOUIS • Several years ago, St. Louis police stopped regularly checking packages for drugs at delivery services like UPS and FedEx.

But employees of those companies may never have known that as, according to federal charges, Sgt. Larry J. Davis still made the rounds. Since Oct. 1, 2010, Davis allegedly collected parcels suspected of containing marijuana but took many home instead of the crime lab.

Davis, 46, of St. Louis, and his brother Linus R. "Bob" Davis, 42, of St. Louis County, were arrested Thursday on two felony marijuana counts: conspiracy to possess with intent to distribute and possession with intent to distribute.

U.S. Attorney Richard Callahan said that Larry Davis "would visit some of the private package companies, they assumed he was acting in his official capacity and he would seize certain packages that looked suspicious. Some of the packages made their way to the police department lab, but the greater number did not."

Prosecutors said the Davis brothers later sold the drugs.

It is not clear how Sgt. Davis was alerted to the presence of the packages. Investigators may use drug-sniffing dogs or look for a parcel's appearance, origin or destination.