(Gary Cameron/Reuters)

A man was arrested at the National Zoo on Monday afternoon after authorities said he left behind a suspicious powder with glass shards in the Reptile Discovery House and the Small Mammal House, according to a spokeswoman.

The D.C. fire department said the substance was not toxic — an official described it as corn starch — but it forced zoo officials to close the two attractions to visitors. The zoo also closed the Invertebrate House because it connects with the reptile house.

Pamela Baker-Masson, a spokeswoman for the zoo, said the three buildings remained closed the remainder of the day so that police could conclude their investigation and workers could clean. The zoo will be closed should the government shut down.

Authorities said he incident occurred about 3 p.m. when a patron notified park officials about the suspicious substance. Baker-Masson said officers with the National Zoological Park Police responded and arrested a suspect. His name was not immediately released pending charges being filed.

Baker-Masson said no visitor nor animal was injured. She described attendance as light.