(CNN) He's accused of killing a teen internet personality and posting gruesome photos of her body online.

Now, Brandon Andrew Clark, 21, is charged with second-degree murder in the death of 17-year-old Bianca Devins, according to Utica police in upstate New York.

Clark is still hospitalized Wednesday after stabbing himself in the neck, police say, when officers responded to a report of a suicidal man who had killed a woman Sunday morning.

The body of Devins, a popular personality among internet gamers, was found under a tarp nearby. Her throat had been slashed.

A motive remains uncertain

Police said Clark and Devins met on Instagram about two months ago and grew close.

They were driving back from a concert in New York City sometime after 10 p.m. Saturday. Authorities said an argument between the two precipitated her death.

"He's with her in the car. The attack happens in the vehicle," Utica police Lt. Bryan Coromato said Wednesday.

"The motive is still something we are looking into. ... We are looking at the dynamics of the relationship, what the relationship meant to him, what the relationship meant to her. There was a relationship, and it potentially was more serious to him than it was to her."

Coromato said he expects Clark to be released from the hospital this week. After that, he'll appear in court to face the murder charge.

Clark has been assigned a public defender from the Oneida County public defender's office. Frank Nebush, the county's head public defender, declined to publicly comment on the case.

Horrified gamers helped contact police

Devins, a recent high school graduate, had amassed a large social media following across several platforms.

She was especially well-known in the online gaming community. And it was on a social app for gamers, Discord, where Clark posted photos of Devins' body, police say.

Members of Discord who saw the ghastly images contacted the Utica Police Department.

"The first call was from Tennessee," Coromato said. "Someone on Discord saw the picture of her. She appeared to be deceased with a large wound on her neck, and it said her name and Utica, New York."

Discord said it is working with investigators.

"We are shocked and deeply saddened by this terrible situation," the company said. "We are working closely with law enforcement to provide any assistance we can. In the meantime, our hearts go out to Bianca's family and loved ones."

The suspect stabbed himself and took selfies, police say

Utica police said they received several 911 calls about a suicidal man who said he killed a woman.

When an officer arrived and found Clark, the suspect started stabbing his throat with a large knife, police said. He didn't respond to the officer's verbal commands, Coromato said.

"He's posting photos of himself," the police spokesman said after watching bodycam footage from the scene.

Clark was eventually hospitalized and underwent emergency surgery.

The slain teen planned to attend college in the fall

Devins' family issued a statement thanking loved ones for their support and prayers

"Bianca, age 17, was a talented artist, a loving sister, daughter, and cousin, and a wonderful young girl, taken from us all too soon," the statement read. "She is now looking down on us, as she joins her cat, Belle, in heaven."

Devins had planned to attend Mohawk Valley Community College in Utica in the fall, her family said.

"Bianca's smile brightened our lives. She will always be remembered as our princess."