TORONTO (CBS) — Toronto Police Chief Mark Saunders said Wednesday officials have found no evidence to support the Islamic State of Iraq and Syria’s (ISIS) claim of responsibility for Sunday’s mass shooting in Toronto that killed two and injured 13. ISIS claimed that one of its “soldiers” carried out the attack in response to its calls to target citizens of the U.S-led coalition battling it. The claim appeared on the group’s social media channels.

Saunders said in a statement that all areas of the Toronto Police Service have been involved in the investigation and they have received assistance from law enforcement partners at every level.

“At this stage, we have no evidence to support these claims,” Saunders said.

Saunders said officials will continue to explore every investigative avenue, including interviews and reviewing the online activity and mental health experiences of dead gunman Faisal Hussain.

Federal Public Safety Minister Ralph Goodale has also said there was no national security risk following the attack

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Hussain died after an exchange of gunfire with police. His family has said he suffered from lifelong “severe mental health challenges” including psychosis and depression and had not responded to numerous treatment approaches, including therapy and medication.

Late Tuesday, authorities identified the 10-year-old girl who was slain as Julianna Kozis of Markham, Ontario. Toronto police released a photo of the smiling, young girl and said her family had asked for privacy during their time of grief. Police previously identified the other person killed in the shooting as 18-year-old Reese Fallon of Toronto.

The mass shooting in Toronto’s Greektown neighborhood stunned people in a normally safe city, already unsettled by an attack just three months ago when a man used a van to plow over pedestrians on a downtown sidewalk, killing 10 people and injuring 14 in an attack apparently aimed at women.