The younger brother, Blaine, was supposed to join his classmates early Thursday on an eighth-grade class trip to Washington.
Kevin Brinkman, superintendent of Ottawa-Glandorf Schools, said the trip went ahead as scheduled. He said a steady stream of students had been meeting with counselors at the two schools the boys attended.
Blaine was on the basketball and track teams, Brinkman said.
Blake was a junior at Ottawa-Glandorf High School, where he was involved in track and choir, principal Jayson Selgo said Friday. The school has about 530 students, and word of his death traveled fast in the community.
"He was very well respected and liked by the students and faculty, as well. A very friendly kid," Selgo said.
Marquis West, who knows all three boys, said they had lived together with their moms for less than a year.
"Every time we got together, they were always uplifting toward each other," said West, an 18-year-old senior at Ottawa-Glandorf High School.
West said he knew the three teens from playing basketball in a church league. The two brothers were especially close, he said, despite their age difference.
"They were always together," West said. "The only time they were separate was when they were on different teams."
Counselors were available in the district for students and staff members who might need help coping with the news.
"I think everyone is trying to get through this difficult time in their own way," Selgo said.
The school posted a notice on its website Friday saying "our thoughts and prayers go out to the family and friends of Blake and Blaine."
Selgo said the 17-year-old in custody did not attend the high school.
The trailer park, surrounded by farm fields on the edge of the village, has a mix of well-kept trailers with neatly trimmed yards and other lots that are overgrown. The trailer where the families live has weeds growing in the flower bed, broken blinds and an autographed football in the window. In the back, there's a motorcycle parked in a shed and a smashed barbecue grill lid and other discarded items on the ground.
Angela Weber, who moved in next door to the family two months ago, said it's a peaceful community.
"We live in a small town for a reason," she said.
Associated Press writers Ann Sanner and Mitch Stacy in Columbus contributed to this report.