A crazed, jealous teenager allegedly gunned down his 15-year-old girlfriend and her younger brother after earlier threatening to kill her if she “messed around with other guys,” according to court documents.

Keith Maurice James Jr., 16, is facing first-degree murder charges after he allegedly gunned down Giovanna Myrie and her 9-year-old brother, Steve Allen, at their Baltimore home on July 7.

Myrie had texted a friend freaking out days before the slayings, saying that James warned her he would “have to kill” her if she “messed around with other guys,” according to charging documents obtained by the Baltimore Sun.

“Keith said if I cheat he finna put the gun inside me. Help me,” she pleaded in a text.

Giovanna Myrie was shot and killed her Baltimore home on July 7. Kaczorowski Funeral home

On the Fourth of July, just days before the slayings, Myrie and James Jr. Facetimed with one of Myrie’s friends while they were hanging out in bed — and the accused killer was holding a gun, the friend told investigators.

On the day of the shooting, Myrie said James Jr. was due to come over to her house around 4 p.m., the friend told police. 

The accused killer’s cellphone data and neighbors’ surveillance footage placed him near the crime scene around 4:20 p.m., according to charging documents.

Myrie’s mother found the teen girl and her younger brother dead from multiple gunshot wounds in the home around 7:20 p.m.

Steve Allen, 9, was an “innocent bystander,” cops said. Kaczorowski Funeral home

Baltimore County Police Chief Robert McCullough said that Allen had been an “innocent bystander.” 

James Jr. told police he had been seeing Myrie for about two months, but had not seen her in person since July 4. He was arrested and charged with two counts of first-degree murder on Tuesday.

Giovanna Myrie and her brother Steve Allen in an undated photo. Kaczorowski Funeral home

He appeared in court in an orange jumpsuit on Thursday and remained silent as his attorney waived his request for a bond hearing, WBFF reported.

The two siblings were found dead at their Baltimore home on July 7. WBFF Giovanna Myrie was found dead in her Baltimore home on July 7, 2026. Kaczorowski Funeral home The scene of the home where two children were found dead. WBFF

“This case highlights for me a couple issues,” the police chief told reporters, according to WBAL. “One is juvenile violence itself, violence by juveniles on other juveniles, and it also highlights the point that, as parents, we need to make sure that we know who our kids are associating with,” McCullough said.

 “It’s just dating violence, teen violence between people who have relationships, so we need to be mindful of those things.”