A prank call alerting of a new tragedy in the Oranovo coal mine in southwestern Bulgaria has sent local police on a wild chase Saturday evening.

The call was placed at 11 pm on the 112 emergency hotline, and a male voice has said he was a professor and wanted to inform that three people have been harmed inside the mine, bTV informed Sunday.

After realizing that the alert was fake, police have traced the call and are now establishing the identity of the cruel prankster.

This happened after the Bulgarian government declared Monday, August 5, a day of national mourning for the four miners who were killed by a collapse in the mine.

The bodies of two missing miners were found Friday, after a difficult 18-day search operation.

Miners Ivan Lazarov, 35, and Nikolay Mihaylov, 42, were trapped 450 meters below the surface underneath an avalanche of mud, rocks and water.

Two other miners, Asen Stoynev, 41, and Hristo Mladenov, 45, died in the collapse as well, but their bodies were discovered on the very same day.

On Thursday, one miner died inside from an apparent heart attack.

A three-day mourning has been declared in the town of Simitli, Blagoevgrad region, near which the Oranovo mine is located.

Bulgaria's cabinet and president have vowed to fully investigate the tragic incident and bring everybody responsible to justice.