Jacob Lee Boyd, 17, was arrested Monday afternoon and remains jailed on a murder charge and a $1 million bond.
Boyd and his estranged girlfriend, Racheal Jean Wiest, 16, met a friend's house on Monday in the 300 block of E. Sixth Street to discuss their relationship, according to Irving police.
The two had been in a relationship for a year and broke up two weeks ago.
Police said the two got into an argument and Wiest attempted to leave the home, but then Boyd began choking her until she stopped moving.
The homeowner called 911 and attempted CPR when he or she found out what had happened. Police arrived on scene and took Boyd into custody without incident, saying he admitted to the crime.
"He did make an unsolicited statement, basically that he had choked her following an argument," said Officer James McLellan with the Irving Police Department.
Wiest was unconscious when police arrived and transported to Parkland Hospital, where she later died.
Irving ISD officials confirmed that Wiest was a sophomore at Nimitz HS and Boyd was a junior at the school.
Grief counselors were at the campus on Tuesday for students and staff.
Wiest's family released a statement late Tuesday, saying they were stunned at what had occurred.
"The events in the last twenty-four hours have been shocking and devastating for both families involved. We ask at this time that you please allow all parties involved the time they need to grieve this enormous loss. We are still in shock and disbelief at losing such a beautiful, young life," the statement read.
When Kendra Bauman, a former neighbor of Boyd's, heard the news, she couldn't believe it.
"He was really nice," said Bauman. "He was a sweetheart. I let my kids play with him."
A memorial fund for Wiest has been set up at http://www.gofundme.com/RachealWiest