A 23-year-old man has been charged with four counts of first-degree murder after four members of his family were found dead in a home in Markham on Sunday afternoon.

Officers were called to a home on Castlemore Avenue shortly before 3 p.m. for a report of multiple injuries at a residence in the area.

When police arrived, a man met officers at the front door of the house. Officers subsequently located one man and three women dead inside the residence.

The victims are the suspect’s mother, father, sister and grandmother, a source confirmed to CTV News.

Police said a suspect, identified as 23-year-old Menhaz Zaman, was taken into custody on Sunday in connection with the incident.

He appeared in court on Monday morning and was formally charged with the murders.

Investigators have not released the identity of the four people found dead inside the home or provided information about their cause of death.

“The identification process for the deceased is going to take quite some time as post-mortems need to be done by the coroner,” Const. Andy Pattenden told reporters during an update on Monday.

“Once those post-mortems are complete, we will be able to advise who the deceased are.”

Sources close to the investigation told CTV News Toronto that police were alerted to the situation by citizens concerned about postings on the murders, allegedly written by the suspect on gaming websites.

On Sunday night, homicide detectives and forensic officers were all on scene investigating.

“Last night was a very active and ongoing investigation inside the house,” Pattenden said. “This scene is going to be held for quite some time as there is a lot of work for forensic (officers).”

Police say they are not searching for any additional suspects.

“This is now a case before the courts… as far as information at this point in time coming out, we are going to be limited in what we can provide,” Pattenden said.

A man, who identified himself only as Rafiq, said he resides in the neighbourhood and has known the family who lives in the home for more than a decade.

“Last Friday, the family went to Bluffer’s Park for a picnic… and they had a good time there,” he said.

“This is a wonderful family. This is a loving, caring father. (It is) unbelievable that this has happened to this family.”

Police are urging anyone with information about the case to contact the homicide unit.

The accused is scheduled to return to court via video link on Aug. 2 at 2 p.m.