Inspired by a credible bomb threat that closed Minneapolis Southwest High School for a day this week, someone targeted another high school in town Thursday with what authorities deemed to be an unsubstantiated threat, a district spokeswoman said.

A threat directed at Washburn High School in Minneapolis prompted the district to put the school on a modified lockdown Thursday and brought police in for a walk-through that found nothing suspicious, said spokeswoman Rachel Hicks.

"In working with police, we determined that the threat to Washburn High School was not credible and that school would operate on a regular schedule today," Hicks wrote in a notice posted on the school's website that also went to families in an automated phone call.

Even though "no unsafe materials were found," Washburn was placed on what the district calls a "code yellow lockdown" Thursday.

This precaution meant classes operated normally, but students remained in their rooms during instruction. Also, outer doors to the school were locked and visitors needed to present identification in order to enter.

Hicks said Thursday afternoon that district officials "believe this was an attempt to get MPS to cancel school after Southwest's closure yesterday."

On Wednesday, authorities found no sign of explosives at Southwest after a bomb threat Tuesday night shut it down.

A police walk-through was conducted Wednesday morning at Southwest, and classes resumed Thursday while a police squad car was stationed outside.

Hicks has not disclosed the source of either threat.

Paul Walsh • 612-673-4482