By Nigel Duara and Jonathan Cooper

Associated Press

TROUTDALE, Ore. — A teen gunman armed with a rifle shot and killed a student Tuesday and injured a teacher before he likely killed himself at a high school in a quiet Columbia River town in Oregon, authorities said.

After the shooting stopped, police spotted the suspect slumped on a toilet in a bathroom but couldn't see what was happening with him.

Police officers respond to a shooting at Reynolds High School Tuesday, June 10, 2014, in Troutdale, Ore. (AP Image)

Officers used a robot with a camera to investigate and discovered the suspect was dead and that he had likely killed himself, Troutdale, police spokesman Sgt. Carey Kaer said.

Authorities have tentatively identified the gunman and the slain student, who was found in a locker room at Reynolds High School, but the names were being withheld until their families were notified, police Chief Scott Anderson said.

The teacher's injuries weren't life-threatening, and he was treated at the scene. He was identified as Todd Rispler, a 50-year-old physical education instructor and former track coach and quarterback at the school.

The attack panicked students after a lockdown was ordered and they were told to go quietly to their classrooms.

Freshman Morgan Rose, 15, said she hunkered down in a locker room with another student and two teachers.

"It was scary in the moment. Now knowing everything's OK, I'm better," she said.

Freshman Daniel DeLong, 15, said after the shooting that he saw a physical education teacher at the school with a bloodied shirt. He said he was texting friends to make sure they were all OK.

"It just, like, happened so fast, you know?" he said.

Anderson said two on-campus police officers were the first to respond to reports of a shooting. The officers and a tactical team sent to the school "brought this to a conclusion," Anderson said, without elaborating.

The chief said he was sorry for the family of the slain student. "Today is a very tragic day for the city of Troutdale," the chief said.

Gov. John Kitzhaber added in a statement: "Oregon hurts as we try to make sense of a senseless act of violence."

The first reports of shots fired came at 8 a.m. on the next-to-last-day of classes. Police initially seemed uncertain about whether there was a live shooter in the school.

Students were eventually led from the school with hands up or on their heads. Parents and students were reunited in a supermarket parking lot.

Mandy Johnson said her daughter called from a friend's phone.

"I thank God that she's safe," said Johnson, who has three younger children. "I don't want to send my kids to school anymore."

The Reynolds School District issued a statement mourning the loss of one of its students.

Reynolds is the second-largest high school in Oregon, with about 2,800 students. The school is about 15 miles from Portland and its students come from several communities.

During the evacuation of the school, authorities found another student with a gun and he was taken into custody. That weapon and arrest were not related to the shooting, Anderson said.

The Oregon violence came less than a week after a gunman opened fire on a college campus in neighboring Washington state, killing a 19-year-old man and wounding two others. It follows a string of mass shootings that have disturbed the nation, including one on Sunday in Nevada that left two Las Vegas police officers and a civilian dead.

The Tuesday shooting was the first fatal school shooting in Oregon since May 1998 when 15-yeatr-old Kip Kinkel killed two students and wounded 25 others at Thurston High School in Springfield near Eugene. He killed his parents prior to the attack and is serving a 111-year prison sentence.

Copyright 2014 The Associated Press