BOSTON -- Students and workers at a Brookline recreation center got a scare Thursday morning after an employee got a threatening letter, police said.

Just after 9 a.m., an employee of the Soule Recreation Center at 652 Hammond St. in Brookline received a threatening letter in her mailbox. The note made reference to her car.

The day care/pre-school which enrolls about 20 children inside the building was evacuated as a precaution. They were allowed to return to the building after the facility was checked out.

The State Police bomb squad was called to the scene and sent in a robot to check out the employee's car.