THORNTON, Colo. (AP) - A high school student whose class project included a soldier memorial display with a replica AK-47 was carrying it to his mom in the parking lot Friday around the time another student and a teacher said they saw someone outside with what looked like a rifle, police said.
Their report of a possible gunman near campus drew armed officers and worried parents to Thornton High School, as several students hunkered down in classrooms and closets. Other students left the school in single file, holding hands and led by police to buses taking them away from campus. An officer was posted in each bus.
Police later found no gunman or weapons and said everyone was safe.
"We've pretty much searched the building," Thornton police spokesman Matt Barnes said outside the school in the northern Denver suburbs. "We've not located anything."
Police said Friday evening that the investigation remains active, but no one has been arrested.
Around 11:40 a.m. on what was the last day of class before summer vacation, a student told a teacher he had seen someone carrying what appeared to be an assault rifle outside, police said. The teacher looked outside and saw the same thing. A school resources officer was notified, and the school went into lockdown mode.
About an hour later, a parent told police she had picked up a school project with a replica rifle from her son earlier in the day. The student told police his history class project involved a replica rifle, helmet and boots typical of a "Fallen Soldier Battle Cross" sometimes seen at soldiers' memorial services.
There were some tense moments, though, while officers investigated the potential threat.
Amy Irsik said she sped to the school, crying all the way, after her 17-year-old son David sent her a text saying the school was on lockdown after the report of an armed man. "I love you," the text ended.
Student Ezequiel Cordova said he left the building at the order of police as an automated message came over the public address system announcing a security problem.
Freshman Haley Johnson, 14, said she spent about 90 minutes in a supply closet that wasn't air conditioned, texting her mother and trying to go online to find out if there was a shooter.
The school has 2,000 students and 130 staff members.
The incident rattled Thornton, a city of 122,000 about 20 miles north of Columbine High School in the southwest Denver suburbs. Law enforcement was criticized for not moving quickly enough after the 1999 attack at Columbine, in which two teenagers killed 12 students and a teacher before killing themselves.
After the Columbine shooting, police across the country developed tactics for responding officers to aggressively rush onto scenes to stop any suspected gunman.