Chicago Mayor Rahm Emanuel Cuts Vacation Short After Latest Police Shooting

— -- Chicago Mayor Rahm Emanuel is cutting his holiday vacation short to deal with the fallout from two people being fatally shot by police the day after Christmas, just as the city is dealing with blowback from another deadly altercation.

Saturday's shooting, which left a 55-year-old grandmother and a 19-year-old man dead, prompted some public outrage Sunday and added to the pile of questions for city officials.

Here is the latest on what we know about the most recent fatal police shooting.

What Happened Before the Shooting

Officers responded to a domestic disturbance at 4:25 a.m. Saturday.

"Upon arrival, officers were confronted by a combative subject resulting in the discharging of the officer's weapon, fatally wounding two individuals," a police statement said.

The two individuals have since been identified as Bettie Jones and Quintonio LeGrier. The Associated Press reports that the police were responding to a call made by LeGrier's father, Antonio LeGrier, who had been arguing with his son.

His mother, Janet Cooksey, has since said publicly that her son, who was studying engineering, had mental health issues.

"He was a student, he worked hard, he cared about people," she said.

In the statement released Saturday night, Chicago police said Jones, who is a grandmother and mother of five, was shot unintentionally.

"The 55 year old female victim was accidentally struck and tragically killed," the police statement said. "The department extends its deepest condolences to the victim’s family and friends."

How Has the Mayor Responded

Mayor Rahm Emanuel put out a statement sharing his condolences and announcing an immediate investigation.

"Anytime an officer uses force the public deserves answers, and regardless of the circumstances, we all grieve anytime there is a loss of life in our city," Emanuel said Saturday. "With that in mind, I have been informed that the Independent Police Review Authority has opened investigations into each shooting, and that all evidence will be shared with the Cook County State's Attorney's Office for additional review in the days ahead."

Emanuel has been under public pressure in recent weeks after the release of dashboard-camera footage from the October 2014 shooting death of teenager Laquan McDonald.

In the fallout of the McDonald case, Emanuel asked Police Superintendent Garry McCarthy to resign. Emanuel himself has been the subject of public calls to step down, but he has said he will not be resigning.

Emanuel has been in Cuba on a family vacation but his spokeswoman, Kelley Quinn, released a statement today saying he is cutting the trip short to arrive back in Chicago on Tuesday afternoon.

Who Is the Officer Who Fired the Deadly Shots

Neither the number of officers involved nor their name or names has been released by police. The identity of police involved in shootings is generally withheld from the public until after the completion of a review of the incident by the City of Chicago Independent Police Review Authority.

The length of such investigations varies in every case, but this will be distinctly different. In the wake of the McDonald controversy, Emanuel also fired the then-head of the Independent Police Review Authority, and former federal prosecutor Sharon Fairley was named as the new head.

ABC News' Emily Shapiro, Alex Perez and Andy Fies contributed to this report.