Swedish police say they have closed an investigation at the Oskarshamn nuclear power plant where traces of an explosive substance were allegedly found in an employee's bag.

Kalmar police spokesman Sven-Erik Karlsson says there is not enough evidence to suggest a crime was committed.

The decision was announced Monday after police received forensic results that could not confirm that a bottle in the bag carried traces of the explosive TNT.

Two maintenance workers were arrested last month after security guards said they detected traces of a highly explosive substance on a plastic bag. The incident triggered a major security alert and officials shut down one of the plant's three reactors to search for a bomb. None was found.