Two decades ago, Allean Logan vanished without a trace from her Washington, DC home. Her newborn son was alone inside the apartment, strapped in his infant seat, his diaper soaked.

“This has just devastated and my rocked my family,” Allean’s nephew, Henderson Long, told Dateline. “It was just so much pain and no answers.”

The 36-year-old mother of two boys was last seen on September 15, 1999. Around 1:30 a.m., family members became worried because Allean hadn’t been answering their calls for hours.

Henderson told Dateline that family members called the apartment manager to conduct a wellness check at Allean’s home on South Capitol Street.

That’s where they found her baby, Jerome, still in his infant seat. The apartment was in disarray and there were indications of a struggle.

“My cousin was still strapped in his little baby seat and his Pampers were soaked,” Henderson said. “He was there, alone, and he was fine, but there was no Allean.”

That’s when the mystery began.

Allean Logan (Photo provided by family)

“For 19 years, my family had no answers,” Henderson said. “Allean’s mother, she was terminally ill. This was literally killing her. So we didn’t talk about it, not for a while.”

In the past few years, Henderson has taken it upon himself to do his own investigation. Allean’s case inspired him to create “D.C.’s Missing Voice,” a platform to help locate missing people in the DC area.

“It’s a passion of mine,” Henderson said. “My aunt inspired me to become this advocate for missing people.”

By 2018, the hard work of Henderson and his family was about to pay off.

That’s when, as part of the ongoing search for Allean, her sisters gave detectives their DNA, hoping for answers.

They got them. Their DNA matched that of a Jane Doe found in 2000, the year after Allean vanished. To be certain, one of Allean’s sons submitted his DNA and in January 2019, the match was confirmed.

“All this time, she had been a Jane Doe,” Henderson said. “Her remains just sat in Baltimore for 18 years. It’s crazy.”

Henderson said police had found his aunt’s body near DC’s Barnaby Terrace neighborhood, about a mile and a half away from where she was last seen.

“It’s just such a tragic story, and it was hard to hear that she has been dead all these years,” Henderson said. “But at least we had some answers. That was something.”

DNA technology provided the answer to one mystery, but another remains: What happened to Allean Logan?

“We believe that Allean was murdered,” Henderson said. “But her body was found a year later, so there were just remains, bones. You couldn’t tell what happened to her.”

Dateline reached out to the Metropolitan Police Department and they confirmed that they are now investigating Allean’s death as a homicide. No arrests have been made.

“We can’t discuss aspects of an ongoing investigation, but please be assured that we follow every tip or lead that comes into our department,” Public Information Officer Sean Hickman stated to Dateline in an email. “MPD works tirelessly to bring closure to all of our outstanding cases.”

Henderson said he believes his aunt’s disappearance was suspicious because he says she had witnessed a murder just hours before she vanished.

“She witnessed the murder of a man across the hallway from where she lived,” Henderson said. “They knew each other. And that day is when she talked to detectives -- right before she went missing.” Public Information Officer Hickman would not comment on what Henderson told Dateline happened that day in 1999.

Henderson said he believed Allean was enticed to come outside and that’s when she was killed.

“I don’t think she ever intended to leave for a long time. She wouldn’t leave her baby alone,” Henderson said. “She was a great mother, an amazing woman. Everyone loved Allean.”

Henderson told Dateline he hopes someone witnessed something that night and will come forward with information.

“I just don’t think anyone forced her outside.” Henderson said. “My aunt was petite, but she was feisty. She was a fighter. She would’ve put up a fight and caused a ruckus. Someone would’ve heard that.”

Henderson told Dateline there was a spike in drug-related murders between 1989 and 1999 in Washington, DC and believes his aunt’s killer may now be dead or incarcerated.

“But I’m gonna press the envelope with this,” Henderson said. “With every lead I can work. Until our family has closure.”

Henderson said Allean’s two sons are now grown and doing well. And at least they now have some answers about what happened to their mother.

He urges people who have missing loved ones to submit their DNA to www.namus.gov, because “it works, the technology works. It could save you years of pain.”

In February 2019, Allean was laid to rest in private service held by her family and friends.

The Metropolitan Police Department offers a reward of up to $25,000 to anyone who provides information that leads to the arrest and conviction of the person or persons responsible for any homicide committed in the District of Columbia.

Anyone with information about Allean Logan’s case is asked to call the police at 202-727-9099. Information may be submitted anonymously to the department’s text tip line by sending a text message to 50411.