The bodies of Cheli's Chili Bar manager Megan Soroka, 49, of Dearborn, and cook Mark Barnard, 52, of Detroit were found Tuesday morning at the hockey star's eatery.
"We believe, just based upon the information right now, that it is a former disgruntled employee that may be responsible for these two murders," Police Chief Ella Bully-Cummings told reporters for the Detroit Free Press and the Detroit News.
The suspect had been fired by the bar about a month ago, said police spokesman James Tate. He could be arraigned on murder charges Wednesday morning.
Soroka and Barnard were found on the restaurant's second floor and were believed to have been killed just before 9 a.m., said police spokeswoman Yvette Walker.
Friends and family say Soroka was an important part in Chelios opening his downtown sports bar. Dedicated and trustworthy, she helped make the bar an instant fan favourite, they said.
Chelios "counted on her for everything because he travels so much," said Lisa Septer, a relative of Soroka who worked with her years ago.
Barnard's mother, Gwen Sharpe, said her son recently told her about problems with an employee.
"I never dreamed it would be carried out like it was on Mark and that poor woman," said Sharpe.
Police questioned other employees who were inside the restaurant at the time of the slayings. The three-story building, which is next to Comerica Park - home of the Detroit Tigers - was cordoned off, and police were scouring the roof.
"We are deeply saddened by the tragedy that occurred at our establishment this morning," Chelios said in a statement. "Our hearts go out to the families of the victims - they were wonderful employees and were part of our family.
"We are co-operating fully with the Detroit Police Department in their investigation and are hopeful the perpetrator will be brought to justice in quick order. We appreciate the community's support at this difficult time."
Chelios, who did not play in Detroit's 2-1 win against Anaheim on Tuesday night, will not travel with the team on Wednesday so he can deal with matters at his bar, coach Mike Babcock said. The Red Wings play in San Jose on Thursday.
Chelios opened the restaurant in 2005 and also has a location in suburban Dearborn.
The restaurant, which has a banner honouring former Red Wings captain Steve Yzerman hanging from an exterior wall, had been expecting a busy night Tuesday because of a ceremony at Joe Louis Arena honouring Yzerman.
Instead, chairs remained on top of tables and a security guard turned away anyone who approached the restaurant.