Police are investigating an incident Wednesday in which a bottle containing a small amount of what the fire department described as "acidic fluid" was thrown on King Street in McCully where homeless people have been camping.

A 52-year-old homeless man at Old Stadium Park told police he heard a noise just after 3 a.m. Wednesday and that when he emerged from his tent, he saw a car on King Street speeding away. On the ground was a bottle "with fluid and a smell."

Police arrived at 3:33 a.m. and evacuated the area, closing King Street between Poha Lane and Isenberg Street about 4 a.m.

The fire department’s hazardous materials unit was called at 3:58 a.m. to assess and neutralize the liquid.

Fire Capt. Terry Seelig said there was an uncapped bottle and about a pint of fluid on the street.

Soda ash was put on the fluid to neutralize it, Seelig said, and the material was placed in a half-gallon bucket.

City road crews disposed of the material, a city Road Division official said.

No one was injured, and the street was reopened a few hours later.

Police initiated an investigation of reckless endangering and manufacture of a prohibitive device.