A Tennessee teen who died by suicide last week was cyberbullied by classmates over his perceived sexuality prior to his death, according to the teen’s brother.

Channing Smith, 16, a high school student in Coffee County, Tennessee, died by suicide between Sept. 22 and Sept. 23. Joshua Smith, Channing’s half-brother, said he discovered the cyberbullying after he was initially unable to identify a motive for Channing’s death.

“I just went out on a limb and started cold messaging kids that were apparently his friends,” Joshua Smith told TODAY.com. “Within just a couple of hours, I was able just from talking to kids to put together a storyline.”

Joshua Smith said he found out that Channing had been sending sexually explicit texts to a boy from school. When a girl Channing had previously dated came across these messages, she shared screen shots on Snapchat and Instagram and “pretty much outs my brother for being gay,” he said.

“I think these kids need to be held accountable at some level,” he said.

Faith Honea, Channing's classmate and friend, said other classmates started cyberbullying the teen who was not out as LGBTQ at the time.

"It just breaks my heart that people found out and made fun of him for it," she said. "The people who exposed him had absolutely no right. They made fun of him, hurt him and above all made him feel alone."

Chris Sanders, director of the Tennessee Equality Project, a statewide LGBTQ advocacy group, said his organization is experiencing “everything from sadness to outrage at the events that took place before Channing took his life.”

“We are listening to the voices of those who love him and attending a meeting tonight to learn how we can be of help,” Sanders told NBC News in an email Monday. “The way forward involves many parts, including better public policy around issues of bullying and more acceptance of LGBTQ youth by community leaders.”

Sanders also said he and his organization are “watching closely for action” by Coffee County District Attorney Craig Northcott “based on his past statements about the LGBTQ community.”

Northcott was criticized earlier this year after video emerged of him making public comments that he would not enforce domestic violence cases in same-sex relationships because he did not believe in their biblical validity. In one video, Northcott said of same-sex domestic violence cases: "There's no marriage to protect, so I don't prosecute them."

Charles Lawson, director of Coffee County Schools, told NBC News in a statement Monday that a "legal investigation" is being conducted into the events leading up to Channing's suicide and counselors would be available for students and staff.

Northcott said his office has "encouraged, cooperated in and supported" the school district's investigation into Channing's death and "no charging decisions have been made."

"I, like the rest of the community, am deeply saddened by the tragic loss of the young life of Channing Smith. I express my heartfelt condolences to his family," he said in a press release. "When all relevant facts are available, my office will advise the Coffee County Sheriff's Department on what charges, if any, we believe are appropriate."

Amit Paley, CEO of LGBTQ youth crisis network The Trevor Project, said he was “heartbroken” to hear of Channing’s passing.

“We know how challenging coming out can be at any age, especially in environments that may include risk factors for increased rates of discrimination, rejection and bullying,” Paley said. “Every LGBTQ youth deserves to know that they are never alone, that their lives have value, and are loved.”

According to a U.S. study released earlier this year, of youths ages 12 to 14 who die by suicide, 1 in 4 may be LGBTQ. Another study found that LGBTQ youth are five times more likely to attempt suicide than their straight peers.

A memorial service was held for Channing on Thursday, which dozens of community members attended. Country singer Billy Ray Cyrus performed with a band for the large crowd.

"Lifting up Channing this morning with his family and friends. His dad David played with us. And thanks to the Manchester, TN community for opening up their park and more importantly... their hearts with me and the band," Cyrus said in a tweet Sunday.

If you or someone you know is in crisis, call the National Suicide Prevention Lifeline at 800-273-8255, text HOME to 741741 or visit SpeakingOfSuicide.com/resources for additional resources. Or contact The Trevor Project, the world’s largest suicide prevention and crisis intervention organization for LGBTQ youth at 1-866-488-7386 or by texting START to 678678.