Niagara police say a 22-year-old Scarborough man is facing two counts of first-degree murder for a double homicide in Fort Erie.
The Thursday morning update comes after police offered up to $100,000 for information that would help solve the killing earlier this year of 20-year-old Juliana Pannunzio of Windsor and 18-year-old Christine Crooks of Toronto.
"We're very emotional. We're relieved but this is step one in a long process," Lisa Mulcaster, Pannunzio's mother, told CBC Hamilton in a phone interview.
In a Facebook message, she added "it makes all of this a reality. A reality that we are never going to see her, hug her, laugh with her or have any more memories with her."
On Jan. 19 around 4:17 a.m. ET, police received a 911 call about possible shots being fired. Officers arrived and discovered the women's bodies in the residence with "obvious signs of trauma."
Pannunzio and Crooks died at the scene from gunshot wounds, police said.
A group of people who weren't from the Niagara Region were staying at the short-term rental accommodation, according to investigators.
People fled before police arrived at the scene.
Two weeks ago, Niagara police said it identified two of the people who were at the Fort Erie home that night, which marked progress in a case where not everyone has cooperated with officers.
The investigation has involved Ontario Provincial Police and police services in York, Durham, Waterloo and Halton.
Niagara police said it made the arrest with help from Toronto police. Niagara police declined an interview and didn't answer any questions about the nature of the arrest or current stage of the investigation.
The person charged in the case, Christopher Lucas, who investigators say is also a rapper known as "El Plaga," is now in custody and was expected to appear for a video bail court appearance at Robert S. K. Welch Court House in St. Catharines Thursday.
Stephanie Sabourin, a spokesperson for Niagara police, did not confirm if Lucas was previously known to police.
Police say the investigation is ongoing and police are asking anyone with information or evidence to contact the Niagara Regional Police Service's homicide unit tip line at (289) 248-1058.