Tyler Robinson, 22, who is suspected of fatally shooting political activist Charlie Kirk on Sep. 10, was reportedly living with a"transgender partner".

Details regarding Robinson's housing arrangement were reported by New York Post and a Fox News digital news correspondent on Sep. 13 (U.S. time).

Axios reported that Robinson's partner was"aghast" at the shooting and was "extremely cooperative" with the authorities.

Who's the partner?

Robinson's partner is said to be in the process of transitioning from male to female, according to a law enforcement source who spoke to New York Post.

Federal and state authorities said earlier during a Friday news conference that a roommate was cooperating with their investigation.

The individual, who has since been identified by the media as Lance Twiggs, 22, is reportedly fully cooperating with the FBI.

Daily Mail further reported that it was Twiggs who apparently showed authorities Robinson's incriminating messages, including texts about stashing a gun.

Authorities got hold of exchanges

The U.S. authorities nabbed Robinson after relying on text messages and other communications that the roommates traded with each other, New York Post reported.

It was also reported that the roommate had apparently shared on Discord the exchanges with a contact named"Tyler", which described bullet casings similar to those found at the scene.

The discussion included the retrieval of a rifle.

Seeking death penalty with aggravated murder charge

The authorities are relying on the messages to seek an aggravated murder charge against Robinson.

This was the only charge in Utah that carries the death penalty.

Law enforcement sources have revealed that Robinson apparently turned himself in to the authorities after being confronted by his own father and speaking with a youth minister, a former sheriff’s deputy, about the shooting.

Background

Robinson grew up in a largely conservative Mormon family.

His family are Republicans.

But Robinson was apparently attracted to the far left in recent years, the authorities said, adding that he was not registered with either political party.

Utah governor Spencer Cox told The Wall Street Journal on Sep. 12 that Robinson"was a person who was deeply indoctrinated with leftist ideology".

Cox also revealed that at a recent family dinner conversation, Robinson and a relative apparently spoke about how they did not like Kirk's viewpoints as a religious conservative activist.

Kirk, 31, was struck in the neck by a single bullet.

He was debating the crowd at his college speaking tour at the time, which touched on the topic of transgender mass shooters.

It is unclear if the shooter took the opportunity to gun Kirk down at that moment or if it occurred by chance.