The line of squad cars, blue lights twinkling in the late afternoon, snaked through downtown, signaling tragic news for Chicago - for the fifth time in six months and the second time this week, a Chicago police officer had been shot and killed.

Stunned shoppers on Black Friday stared as a line of squad cars began to escort the body of Officer Michael Flisk from Northwestern Memorial Hospital on the Near North Side to the Cook County medical examiner's office on the Near West Side.

Flisk, 46, an evidence technician who was two months from celebrating 20 years on the job, had been shot in the head about four hours earlier in a South Side alley where he was investigating a burglary. A 44-year-old man who had called police after his car was broken into was also shot and killed.

News of Flisk's slaying set the department reeling, leaving officers crying in the cold night outside the Cook County morgue and a South Side family of police officers remembering the brother who took on the caretaker role for his brothers and sisters.

"He was the one who kind of smoothed everything over with everybody,'' said Gina Flisk, a sister-in-law of the officer, a married father of four. "He wasn't the oldest, but he was the one who kind of took care of making everybody happy."

Flisk was the sixth Chicago police officer to die violently this year. A sergeant died in a car crash in February while responding to a burglary. Since May, four other officers - all off-duty - had been gunned down. The latest of those killings took place just four days earlier when Officer David Blake was found slain in his SUV. No arrests have been made in that killing.

A longtime officer who heads up the patrol officers union called 2010 the deadliest year for Chicago cops in recent memory.

"There hasn't been a year this bad since the 1960s," said Mark Donahue, president of the Fraternal Order of Police. Officers "are just trying to cope," he said.

Flisk's job as an evidence technician is one of the unheralded but critical roles in the department. Technicians arrive at a scene - often alone - after a crime has been committed to comb for evidence that could lead to an arrest. They rarely get the accolades when their work helps solve murders, rapes and even burglaries.

But the job usually keeps them from the front-line danger many officers face daily.

"It was supposed to keep him safer,'' neighbor Pauline Lewellyn, sobbing in her Beverly kitchen, said of his promotion to evidence technician 31/2 years ago.

Flisk, who was in uniform and driving a marked squad car, was called to a burglary in the 8100 block of South Burnham Avenue on Friday afternoon. The owner of a Mustang GT - identified by his sister as Stephen Peters - had discovered that his car had been broken into in the garage.

Peters called police to report the burglary just after noon, police said, and Flisk was dispatched about half an hour later. Resident said they heard gunshots at about 1:30 p.m. Arriving minutes later, officers found Flisk and Peters lying in the alley mortally wounded from gunfire.

What happened in that hour or how the shootings unfolded was still unclear Friday night.

Peters, who once worked as a police officer for the Chicago Housing Authority, was a married father of three and a car aficionado known as "Superman'' in a Mustang car club, said his sister, Pamela Reed. She described her brother as a hard-working Army veteran who worked for AT&T.

Reed said her mother heard four shots from inside her home - in two different bursts. She then looked out the window.

"She saw my brother lying out in the alley dead," Reed said.

In the aftermath of the shootings, Chicago police literally sealed off the South Chicago neighborhood with crime scene tape and squad cars and began an aggressive search of alleys and trash bins, using dogs. SWAT officers and tactical teams - some carrying M4 rifles - swarmed the area. Motorists and pedestrians were stopped and questioned or asked for identification.

"We will squeeze that neighborhood, and we will find the people who did this,'' a visibly tense police Superintendent Jody Weis said outside Northwestern Memorial Hospital. Police announced a $10,000 reward for information leading to the arrest and conviction of Flisk's murderer.

Flisk came from a family that dedicated their lives to public safety. All but one of Flisk's four siblings were also Chicago police officers. Their father, also named Michael, retired after about three decades with the Chicago Fire Department.

In his Beverly home, Flisk was a neighbor who fixed cars and organized block parties. He was a regular at his son's baseball games. He "wore his heart on his sleeve," one neighbor said.

His marriage was one that others admired too. Neighbors recalled last Christmas when his wife bought Flisk a Harley-Davidson motorcycle and his two boys wheeled it down the street for him.

Late Friday inside the Flisk home, friends and relatives had gathered around the family in quiet support. Outside, neighbors cried and carried hot coffee to the house.

For one neighbor, her last image of Flisk was him raking leaves in the front of his house the other day.

Lewellyn said she kidded him that he should have his children doing the chore.

He just laughed and kept raking.