The Southeast Washington man accused of having a long-term incestuous relationship with his teenage daughter before fatally stabbing her and dumping her body in a trash bin pleaded guilty Friday to first-degree premeditated murder while armed.

In exchange for the plea, prosecutors agreed not to pursue additional charges against Rodney J. McIntyre, 45, in connection with the slaying of 17-year-old Ebony Franklin.

Franklin’s body was found in a trash bin in an alley behind the 1000 block of Fairmont Street NW in Columbia Heights on Nov. 28. She had been stabbed 15 times, according to a medical examiner’s report, and McIntyre’s semen was found in her body. McIntyre was arrested and charged with murder in May.

With McIntyre standing next to his attorney, Elizabeth Mullin of the District’s Public Defender Service, D.C. Superior Court Judge Lynn Leibovitz asked him whether he understood the charges and had agreed to plead guilty. “Yes, ma’am,” he replied.

Prosecutors agreed to seek a sentence of not less than 37 years in prison and not more than 40. If McIntyre had been found guilty of the charge at trial, he could have faced as much as 60 years in prison. Sentencing is scheduled for Oct. 27.

Franklin was raised by her mother in Capitol Heights, according to Assistant U.S. Attorney Jocelyn S. Ballantine, and she reconnected with McIntyre after he was released from prison in 2008. Court records show that McIntyre had been in and out of jail on drug, robbery and other charges since the mid-1980s.

Some students and employees at Cardozo Senior High School in Northwest, which Franklin once attended, thought that McIntyre was Franklin’s boyfriend because of the way she would phone him to bring her lunch and because he would give her money for clothes or sneakers, said Rodneka Preston, 23, Franklin’s half sister.

“He never tried anything like that with me” or Preston’s other sisters, Preston said, referring to the sexual relationship. “But he always favored her. Whenever we wanted something, he didn’t have anything for us. But whenever Ebony phoned, he would jump.”

But Preston said she and her three other sisters didn’t think that it was strange or suspicious that McIntyre favored Franklin. They didn’t learn about the sexual relationship, she said, until after Franklin’s body was discovered and McIntyre was arrested. Preston said she thought that Franklin threatened to expose the relationship, prompting McIntyre to kill her.

Authorities investigating the case declined to comment.

Renee Preston, Rodneka’s mother, said she was in a 13-year relationship with McIntyre that ended nearly a decade ago. She said that she thinks McIntyre had as many as 20 children by other women but that she is sure that he never raped any of her daughters or grandchildren.

“If he had,” Renee Preston said, “I guarantee you, he wouldn’t have been alive long enough to make it to jail.”

Franklin had planned to meet her father in Columbia Heights and spend the weekend of Nov. 26 with him, court papers say. But McIntyre told Franklin’s mother that their daughter planned to spend the weekend with her boyfriend.

McIntyre told police that he and Franklin were supposed to meet in front of the Target store in the 3100 block of 14th Street NW at 1 p.m. Nov. 26 but that she never showed up or called, according to court papers.

Authorities said McIntyre used his daughter’s cellphone to make calls and send text messages to her mother and stepfather in an effort to make it appear that someone else was responsible for her slaying. In one message, authorities said, McIntyre wrote, “Remember, the bitch told on my man now yoo get her out the trash.”

McIntyre worked as a custodian at the now-defunct Keely’s Boxing Gym in the 2500 block of 11th Street NW, within a block of where Franklin’s body was found. Ballantine said McIntyre had placed Franklin’s body in the trash bin and covered it with trash.

According to court documents, authorities determined that on Nov. 27, between 2:47 and 4:28 p.m., McIntyre’s cellphone had been used near where the body was discovered. McIntyre denied being in that area.

Police interviewed McIntyre numerous times, according to court papers. During one interview, they confronted McIntyre about a possible sexual relationship with Franklin. When asked whether his DNA would be on the victim, he told detectives, “I don’t know how to explain it,” and he said that he would not admit a relationship to them but that he would tell Franklin’s mother.

When Franklin’s body was found, authorities determined that his semen had been inside her for as long as three days. McIntyre then told police that he gave Franklin a bottle of his semen, which he said she used in an attempt to become pregnant.

After authorities challenged his statement, McIntyre admitted that he and his daughter had sexual relations on “several occasions,” including a day or so before she was killed.