Now, police are turning their attention to other homicides in the capital to see whether there are any links to these cases.
Marc Leduc, 56, appeared in court Thursday morning on two charges of first-degree murder.
The families of the victims, Pamela Kosmack and Leanne Lawson, were relieved when told of the arrest, police said.
"We have evidence that has led us to lay charges against Marc Leduc in these two cases," Ottawa Police Chief Charles Bordeleau told a news conference.
"Pamela and Leanne were members of this community, our community, and they were victims of senseless homicides."
While police continue investigating other unsolved sex-trade slayings in the city, Bordeleau would not draw an immediate connection to the Kosmack and Lawson deaths.
But he said police would be scouring other files to see whether there might be ties.
"Obviously we are looking at all of our other unsolved homicides to determine whether there are any investigative opportunities with respect to those," he said.
The city has four unsolved cases of murdered women dating back over the last 22 years.
Bordeleau also repeated previous warnings to sex-trade workers and other women in the National Capital region to be vigilant and watchful for potential predators.
"Our message continues," he said. "If you don't feel safe, please reach out to us. Your safety is important to us and we can help."
Kosmack, 39, was found beaten to death on a bike path in June 2008.
Lawson, who was 23, was found dead in a parking lot in September 2011.
DNA evidence played a role in the case, said Bordeleau, who would not reveal other details, saying the investigation continues.