Toronto police have laid new charges against Calvin Michael Nimoh for a separate stabbing and robbery just hours before Mark Ernsting's body was found on McGill Street. 

Nimoh, 21, is charged with second-degree murder in the death of Mark Ernsting, 39, who died after he was attacked near 38 McGill St., just east of Yonge Street and close to Ryerson University, around 9:30 p.m. on Dec. 15.

Police have also arrested and charged two women alleged to have helped Nimoh stab and rob a 65-year-old woman of her purse.

The alleged incident also took place on Dec. 15. at about 7:45 p.m. in the Summerhill Avenue and Yonge Street area.

Toronto Mark Ernsting stabbing victim

Mark Ernsting, a 39-year-old biomedical engineer, died Tuesday night after being attacked and stabbed while out for his evening walk. (Ontario Institute for Cancer Research)

On Christmas eve, a 17-year-old girl and 24-year-old Tia Thompson were arrested. The 17-year-old cannot be identified under the Youth Criminal Justice Act. Each was charged with the following: 

  • Robbery.
  • Aggravated Assault.
  • Possession of Property Obtained by Crime.

Thompson also faces the following charges in Ernsting's homicide:

  • Accessory after the Fact to Murder
  • Obstruct Peace Officer

Thompson appeared in court on Dec. 24, and Nimoh is scheduled to appear in court on Jan. 7, 2016.

His new charges connected to the robbery are: 

  • Robbery
  • Assault with a Weapon
  • Weapons Dangerous