New surveillance video of a suspected serial killer terrorizing Chicago shows a man cops say is a cold-blooded killer who walks like a duck.

In one video, which was shot Sunday, the suspect is seen walking down a quiet street in a black track suit with a hat and scarf covering his face on a warm day.

Moments later, police say he fatally shot 73-year-old Douglass Watts, who was out walking his dogs.

He took off on a run and was caught on surveillance fleeing the shooting scene at about 10 a.m.

Thirty-six hours later and six blocks away, police say he gunned down a second man who was taking a stroll on a lakefront bike path.

That victim has been identified as 24-year-old Eliyahu Moscowitz. Both men were shot in the head at point-blank range.

Police are now out in force in a desperate bid to find the killer, and the suspect's strange duck walk could hold the key to his capture.

Inside Edition spoke to orthopedic surgeon, Dr. Mark Klion about the suspect’s distinctive stride.

"He was kind of off balance and kind of using a wide gait. That, along with what we call a ‘duck walk’ per se, could really identify him as a unique individual," he said.

Chicago has been plagued by gang violence but Rogers Park, a quiet neighborhood near Loyola University, is in shock over the seemingly random murders.

Terrified residents packed a meeting Wednesday as police briefed them on the so-called Duck Walk Killer.

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