Utah prosecutors filed a murder charge on Tuesday against the man accused of assassinating U.S. conservative activist Charlie Kirk, while releasing new details of the high-profile case.

Tyler Robinson, 22, faces multiple charges including aggravated murder, obstruction of justice, felony discharge of a firearm causing serious bodily injury, witness tampering, and committing a violent offense in the presence of a child, Utah County Attorney Jeff Gray announced at a press conference.

Gray said he had independently decided to pursue the death penalty "based solely on the available evidence and circumstances, and nature of the crime."

Robinson made an initial court appearance via video from jail on Tuesday afternoon. Gray presented all seven charges against Robinson during the hearing, with the next court date scheduled for September 29.

Prosecutors also disclosed private text messages in which Robinson allegedly admitted to the shooting.

"I had enough of his hatred," he reportedly told his roommate when asked why he had committed the act, according to court documents.

Utah Governor Spencer Cox previously told local media that Robinson was not cooperating with law enforcement and had not confessed, but friends and family were cooperating.

According to CNN, Robinson's acquaintances said he had been deeply influenced by leftist ideology.

Some politicians, including U.S. President Donald Trump, have publicly called for capital punishment in the case.

After the death of Charlie Kirk

Kirk, 31, co-founder of the conservative student movement Turning Point USA and a close Trump ally, was fatally shot while addressing an audience of 3,000 at Utah University.

Kirk's killing has further deepened political divisions in the U.S. in the nation.

Online debate has largely shifted away from gun violence toward partisan blame. Some accuse the "radical left" of suppressing free speech and even resorting to violence against those who invite peaceful debate, while others fault conservatives for fueling hatred and downplaying attacks on their opponents.

"We have deeply polarized politics, with many Americans viewing the other party not as wrong but as an existential threat," Christopher Galdieri, a political science professor at Saint Anselm College in the northeastern state of New Hampshire, told Xinhua News Agency.

Top administration officials have threatened to pursue left-wing groups in the wake of the assassination, which Trump blamed almost immediately on the "radical left." Critics, however, warned he may use the killing as a pretext to crack down on his political opponents, Reuters reported.

"While many leaders admirably condemned Kirk's killing and political violence generally, and urged people to stay calm and wait for the facts, we saw the Trump Administration spin up talk about going after people who 'contributed to' the shooting," Galdieri said.

(With input from agencies)