Police are investigating the presence of deadly substance ricin in a hotel room at an Extended Stay America hotel in Las Vegas, Nevada Thursday.

A man brought to the manager’s office a bag holding a small container. He said that he found the bag while he was retrieving his items from a hotel room.

Police could not tell who left the bag there and why. Preliminary tests found that the substance was ricin. Additional tests are being carried out by the Centers for Diseases Control and Prevention and a second lab, whose results are expected Friday, police said.

It's “100 percent ricin,” said Capt. Joe Lombardo of the Las Vegas Metropolitan Police Department. “We don't know who (the ricin) belongs to or why it would be here at this time.” He added that there are no suspects for the time being, but at this point “this is not a terror incident.” Lombardo said that authorities found castor beans in the room and powder in a small vial, CNN reports.

Police surrounded the area of Valley View between Flamingo Road and Harmon Avenue, and the people residing at the Extended Stay America were not allowed to enter the building late Thursday, Las Vegas Review-Journal notes.

Ricin is known to be a deadly toxin and even a small amount such as 500 micrograms can kill an adult. Ricin poisoning symptoms include difficulty breathing, fever, cough, nausea sweating, vomiting and dehydration.

Three hotel employees and another person were taken to hospital to be examined, and decontaminated. Three police officers who searched the room were taken to hospital. They have not showed the above mentioned symptoms. It takes between six and eight hours for someone exposed to ricin to show signs of contamination.

Ricin is made from the waste left over from processing castor beans. It can come in the form of a mist or pellet and it can be dissolved in water or weak acid, the CDC reports. Ricin is not considered an illegal substance to own, but it is illegal if used for the purpose of poisoning someone.