REDWOOD CITY -- Authorities Monday were investigating an acid-filled bottle that sprayed a 10-year-old girl outside a Redwood City church over the weekend -- the fourth device of its kind found in San Mateo County in a month.

At about 10:15 a.m. Sunday fire officials received a call reporting a Coke bottle containing an unknown chemical substance outside of the Redeemer Lutheran Church, near the intersection of Grand Street and Harrison Avenue, Battalion Chief Steve Cavallero said.

A group of children had apparently kicked the bottle, breaking the cap. The liquid spurted out of the bottle onto a girl's nylon clothing, melting a few holes in it, according to Cavallero.

The girl, unharmed by the chemical, reported the incident, and the fire department called in the hazardous materials team, the San Mateo Sheriff's Office bomb squad, the Redwood City Police Department, and the county's environmental health department, Cavallero said.

Authorities determined that the liquid inside the bottle was hydrochloric acid. The bottle also contained residual of some kind of metal.

Portions of Grand Street and Harrison Avenue were cordoned off, and church visitors were asked to move their vehicles out of the immediate area. A pastor conducting service in the church was informed and cut the service short, Cavallero said.

The hydrochloric acid that had spilled into the area was safely removed, and environmental health officials safely disposed of the Coke bottle.

Streets were reopened and the scene cleared at about 1:25 p.m., Cavallero said. No injuries were reported.

Officials believe that the incident might be connected to three similar cases in the southern part of San Mateo County in the last month in which two-liter soda bottles were discovered with small amounts of a reactive liquid and metal inside, Cavallero said.

In each of the cases, the substances were mixed and the bottle sealed, creating a reaction that causes the bottles to burst and spray out whatever liquid is inside, he said.

Investigators believe the incidents are meant as pranks, but Cavallero cautioned that whatever liquid used in the bottle can be sprayed onto people nearby and cause harm.