There was a sudden moment of horror at Calvary Baptist Church at Wan Tho Ave in the morning at 10 o'clock yesterday.
A 26 year old cleaner brandished a chopper and threatened to kill people. He managed to injure some of his colleagues.
He was seen chasing some of the church workers with the knife before he was finally arrested by the police.
The 26 year old cleaner was a sub contractor outsourced from a company.
It is suspected that he may have been suffering from a mental illness and that caused him to snap and attack his co-workers.
Although the church's kindergarten was still in session, the church staff immediately initiated procedures to block the madman's access to the church offices and the classrooms.
Three church workers were injured and were subsequently sent to Tan Tock Seng Hospital for treatment.