CHICAGO (AP) -- Federal authorities released a sketch Tuesday of a man they are calling a person of interest in the two pipe bombs mailed to companies here and in Kansas City last month.

The man depicted in the drawing was seen by a witness in the lobby of a suburban Chicago post office on Jan. 26, the day the packages were mailed, according to the Postal Inspection Service. He was wearing tan pants and a dark gray or olive military-style jacket.

"All I know is, he was in the post office," said David Colen, a spokesman for the Postal Inspection Service's Chicago division. "He was there at the right time."

One of the packages arrived Jan. 31 at American Century Investments' midtown Kansas City mail facility. The other was found the next day at a business in a 65-story skyscraper in downtown Chicago.