One man is in custody pending psychological evaluation and an unidentified substance is being tested in a lab following the hazmat scare in Allston on Sunday.

Police closed down part of the neighborhood after receiving a tip about a clear plastic container with the words “danger napalm” written on it placed on Brighton Avenue, police said Monday. A second suspicious package was later discovered nearby on Harvard Avenue, police said.

Bomb and hazardous materials investigators later deemed the area clear to re-open, police said.

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Police arrested Stephen Michael Schroder, 23, at his Brighton home. Schroder, who police said was not a student, faces charges for disturbing the peace and two counts of use of a hoax explosive device.

Schroder was set to undergo pschological evaluation at a nearby facility following a meeting with a court clinician, according to a spokesperson for the Suffolk District Attorney. He was scheduled to return to court Sept. 11.

A witness reportedly told police they saw Schroder place a similar container behind 90 Harvard Ave. Officers soon after arrested the man on prior arrest warrants, according to a report.

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In his home, investigators found other “suspicious substances,” but the BPD hazmat team determined the substances were harmless and disposed of them, according to the report.

Boston Police Commissioner William Evans told reporters Monday that some suspicious substances related to the incident were being tested in a lab.

At the press conference, Evans touted the importance of "see something, say something" policing and thanked the unnamed witness for coming forward.