A 42-year-old resident of a facility for psychiatric patients got past security guards at the Willis Tower in Chicago last week and made his way to the 102nd floor before he was tracked down and held for police, said a Chicago Tribune report.

He was charged with misdemeanor criminal trespass and released on his own recognizance after he followed an employee through a turnstile and got into an elevator, the report said.  he incident happened about 4:35 p.m. on May 16.

A spokesman for the Willis Tower said in a statement released to Fox News that the man was spotted by security in a freight elevator and was in the building for 16 minutes. He  went up to the 102nd floor and on his way down was arrested on the 32nd floor, the statement said.

The spokesman called the event an isolated incident  "At Willis Tower, safety is our utmost priority," the statement said in part. "We are aware that an individual entered the building on Monday, May 16. Through our security systems and procedures, we were able to track and detain this individual within 16 minutes.”