Police say 29-year-old Jayme Pasieka will also face two charges of possessing an offensive weapon.
At a Saturday media briefing, police described Pasieka as being "cooperative" and "calm" after a three-hour manhunt that eventually led to his arrest.
"I can tell you that he has been very calm, very polite and he has been cooperative. I won't be able to go into details of what he has told us, or what he has talked about," said Staff-Sgt. Bill Clark.
Police said Pasieka worked at the warehouse.
A day earlier a man with a knife in each hand wearing a protective vest burst into the Loblaws warehouse and started stabbing people through the complex.
Two people were killed in the attack and four others were hurt, two seriously.
At Saturday's briefing, police identified the deceased as Fitzroy Harris and Thierno Bah.
"As can be expected the families are devestated that their loved ones would go to work and then never come home," Clark said.
Friends confirmed to CBC Edmonton that Bah was a married father of four who recently moved to the city from Montreal with his family.
A member of the Guinean community, Bah had 30 minutes left in his shift when he was killed.
The attacker fled the scene and was arrested without incident three hours later when his vehicle was spotted by an alert citizen.
The weapons used in the attack have not been found, police say, and they have not said what the motive was for the attack.
The two victims who were injured have been treated and released from the hospital.