Ottawa Police arrested a 56-year-old man Wednesday morning in connection with the murders of Pamela Kosmack and Leanne Lawson.

Kosmack's body was found near a bicycle path in Lincoln Heights Park in June 2008.

The 39-year-old Kosmack was a mother of two young children.

Lawson's body was found in a parking lot next to a Hydro Ottawa substation on King Edward Avenue in September 2011.

Lawson was 23 years old.

Police sources tell CTV Ottawa the suspect was already in jail at the Ottawa Carleton Regional Dentention Centre serving time on other charges.

Sources say the suspect's DNA matched evidence gathered in the Kosmack and Lawson cases.

Wednesday's arrest comes more than one year after former Police Chief Vern White issued a public warning to women because of a pattern that indicated a serial killer may be targetting sex trade workers in the capital.

Charges are expected to be laid on Thursday.