Rewind To The Crime: Who killed Delores Rivers?

It has been a year since a 75-year-old grandmother was found murdered inside her Bladensburg home. The killer was apparently allowed into the apartment before strangling her and leaving her body in the bathtub. Detectives said it was not a random crime.

On a recent weekday afternoon, Prince George's County homicide detectives decided to revisit the apartment building where Delores Rivers lived alone and was found murdered on Nov. 5, 2016.

Since then, investigators have been trying to learn who the 75-year-old woman may have allowed into her apartment at some time after 4 p.m. that day.

"Her peephole was clear," said Rivers' daughter, Karen Nelson. "When I went in there, I revisited the peephole just to make sure. You know, some are cloudy. I could see straight to the front door of the front entrance."

Nelson and her sister, Angela Barnes, said their mother never would have opened her door to anyone she did not know. They learned what happened to their mother when Barnes received a call from her brother.

"He was crying on the phone and said, 'Angela, I found ma in the bathroom and she is in the tub and she is not breathing,'" Barnes recalled. "I'm panicking, trying to figure out what to make of it and the only thing I can say is, 'Stay right there, I am on my way.'"

Outside of the apartment, they found their brother William in tears.

"He is on the ground trying to get himself together," said Barnes. "It was really emotional that day."

"They were very close," said Nelson. "They would go to the markets on the weekends. Very close."

Police and family members said there was nothing taken from the apartment. It was not ransacked and there was no forced entry to the front door.

The last time anyone heard from Rivers was the day before her body was found inside her apartment. She had two phone conversations - one with a relative and one with a friend from work. Both of them told police those conversations were normal and there was nothing out of the ordinary.

A year later, her murder remains unsolved.

"We have been doing numerous interviews," said Prince George's County Police Lt. Felipe Ordono. "We are going to continue to work on this case. It is our belief that the suspect in this case was familiar with her or she was familiar with the suspect. We do not believe this was a random act by any means."

Ordono and Sgt. Ken Doyle said the killer used a weapon, a ligature, to strangle Rivers. However, they declined to say if it was found at the scene.

"Nothing really looked to be out of place inside the apartment," said Lt. Ordono. "Nothing was taken that we can prove."

Rivers spent her career working as a technician at the now-closed D.C. General Hospital. She retired on a government pension, but kept busy with a job as a bus aide with Prince George's County Public Schools. She did not drink, she did not smoke and she went to church. Her wild side? A tattoo of a bird she had etched on her leg.

Video of Rivers taken from a birthday party shows her displaying her dancing moves. Her family calls it "Go-Go Grandma."

"She was a fun grandmother," said Alexa Harris. "Very funny, cracking jokes, dancing. She liked to make sure every family event we had, we had a good time and she would get up and dance."

One year later, Rivers' daughters still can't believe she is gone.

"I miss being to have her call me up and say she has this juicy story she wants to tell," said Barnes.

"I miss the school bus stories," said Nelson.

"I miss hearing her voice," Barnes said.

"This is just not right," Nelson said. "It's unfair. She didn't deserve it, and if somebody felt like it, then it's like something very evil that is walking out here."

When police recently went back to Rivers' apartment complex to knock on doors, it was a visit that paid off with a new lead to follow, and the information they received appeared to match part of their investigation.

There is a $25,000 reward being offered in this case. If you know anything that may help investigators solve Rivers' murder, you are asked to contact Prince George's County police.