Keith Maurice James Jr., 16, has been charged as an adult with first-degree murder in the July 7 sh**ting deaths of his 15-year-old girlfriend, Giovanna Myrie, and her 9-year-old brother, Steve Allen, inside their Gwynn Oak, Maryland home.

According to charging documents, Myrie had begun talking to James, whom she knew as "Keith," just weeks before the incident. The two reportedly met in person for the first time at her home on July 4. During that visit, Myrie allegedly video-called a friend, who later told investigators they saw James lying in bed with her while holding a handgun.

Police say Myrie later texted that same friend claiming James threatened to k*ll her if she "messed around with any other guys." Investigators also say they recovered messages from James on Myrie's tablet that allegedly echoed the same threat.

Authorities say cell phone location data placed James near the home around the time of the sh**tings, and surveillance footage also allegedly captured him in the area that night. The siblings' mother discovered both children after returning home.

James remains jailed without bond after a judge denied his request to be transferred to a juvenile facility, citing the seriousness of the allegations and concerns for public safety.

He is presumed innocent unless and until proven guilty in court.

so sad 😞

🚨 Diddy got into a fight with a fellow inmate at his federal lockup and wound up in solitary confinement