MARTINEZ -- A highway offramp was shut down and neighbors were on alert after someone reportedly began firing a shotgun on a residential street Thursday afternoon.

The Contra Costa Sheriff's Office received a call at 3:30 p.m. reporting that someone was firing rounds into the air in the 4700 block of Pacheco Boulevard.

As a precaution, the Pacheco Boulevard offramp of Highway 4 was temporarily closed. The unidentified suspect was taken into custody at about 4:20 p.m.

Deputies later discovered some unknown chemicals inside the house and called a hazardous materials crew. The Sheriff's Office is continuing the investigate the incident.

Check back for updates.

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