Tysean Lipford, 19, at left, is accused of killing Christian Matthews, 17. (From left: Montgomery County Police; Kevin Jones)

A 19-year-old man, wearing gloves, entered the bedroom of a teenager sleeping on an air mattress in suburban Maryland and choked him to death, authorities said Friday.

The attack, just after midnight on Tuesday, claimed the life of Christian Leroy Matthews, 17, who lived in a townhouse in the Colesville area of Montgomery County. Police said he knew the suspect, who had dated his sister and had a child with her.

Detectives working the case got their big break Thursday when the suspect, Tysean A. Lipford, confessed to going into Matthews’s bedroom in the basement and placing him in a choke hold until he was unresponsive, according to a police affidavit filed in court.

Lipford, who did not live in the townhouse, told detectives that he disposed of the gloves after the attack, authorities said.

And he allegedly spoke about a possible motive. Lipford said that sometime before the attack, he overheard Matthews telling someone on the phone that he intended to kill Lipford, Lipford’s daughter and other family members, according to police accounts.

Matthews was kind to neighbors. Here he reads to Matias Jones, center, and Lucian Jones. (Kevin Jones)

“Lipford claimed he feared the victim would carry out the threat,” detectives wrote in court papers.

Lipford was ordered held without bond Friday. He has been charged with first-degree murder. It was unclear whether he has retained an attorney.

Matthews, who lived in the townhouse with his mother and sisters, had gone through bumps in his young life and was attending a public school for students who had struggled either academically or behaviorally. At the same time, people who knew him were quick to describe him Friday as outgoing and compassionate.

“He was always wanting to talk with someone. He had the biggest smile,” said Jessie Tressler, a member of International Community Church in Frederick, where Matthews went to services.

Matthews moved into the townhouse a little less than a year ago, said a next-door neighbor, Kevin William Jones, 37.

A short time later, Jones lost his 6-month-old daughter when the girl got stuck and suffocated. Something about having the friendly teenager coming over often, helping Jones with his other children, telling Jones how much he admired him as a father, drew them together, Jones said.

“He helped us get through our loss,” Jones said. “He was a real agent for good.”

Christian Matthews, 17, who lived in this Montgomery County townhouse, was killed March 21 in the basement. (Dan Morse/The Washington Post)

Jones said he slowly became a mentor to Matthews. That led to discussions about problems that Matthews had at school, including an altercation with another student motivated, Jones said, by Matthews’s desire to show others he wasn’t going to be messed with.

Jones said he felt perfectly fine leaving Matthews alone to care for his sons, 2 and 4. “They loved him,” he said.

“Christian had many circles,” Jones said, “but I knew the circle we had always retained a sense of honor.”

Jones knew the suspect, Lipford, from his visits to the neighborhood, and knew there was bad blood between him and his young friend. “Christian considered him his enemy,” Jones said.

But Jones said Lipford could show a softer side. He would see him and Matthews’s sister go on walks holding hands

Court records in the case describe a violent attack.

According to arrest records, police were called to the Mondrian Terrace residence at 2:25 a.m. Tuesday “for a report of a suspicious situation.” Once there, officers spoke with several occupants, who said that just before calling police they “heard a loud commotion coming from the basement area,” the records state.

In the basement, police found Matthews unresponsive, with bruises around his neck. He was taken to a hospital and pronounced dead, police said.

The “investigation revealed that the victim did not get along with the father of his niece,” detectives wrote. That man, they said, was Lipford.

On Thursday, Lipford came to police headquarters for what detectives described as a “non­custodial interview,” meaning that, initially at least, he would have been free to leave.

“During the interview, Lipford stated that the victim despised him and had intimidated him on numerous occasions,” detectives wrote. “According to Lipford, he recently overhead the victim talking on the telephone, stating he was going to kill Lipford, his daughter, and the rest of his family.”

“Lipford confessed to killing the victim,” detectives wrote. “Lipford stated that he entered the victim’s bedroom, while the victim was asleep. Lipford placed the victim in a chokehold until the victim became unresponsive.”

Lipford then left the house without trying to revive Matthews or calling 911, police said.

Friends of Matthews’s talked Friday about the last time they saw him. For Jones, it was late Monday night, when the teenager saw his lights on and knocked on the back door. They spoke about Matthews trying to stay on a narrow path.

Tressler, at the church in Frederick, recalled seeing him after the service on Sunday, at the altar praying.

Jennifer Jenkins and Julie Tate contributed to this report.