Two officers and one detective entered the frigid waters without any diving gear, after Thursday's relatively mild temperatures made for a dangerous situation on the ice.
It happened shortly before 5 Thursday evening at a retention pond near a condo complex at Lake Bluff Drive and 167th Street.
"We received a phone call from a resident who said there were two girls playing on a pond on the ice," said Tinley Park Police Chief Steven Neubauer. "She was concerned that they might fall through and asked us to send police. About a minute later we received another 911 call that the girls had fallen through the ice."
The two girls, both in their early teens, were about 20 feet from the pond's edge in six feet of water.
"For the situation, (they were) surprisingly calm," said Russell Borrowdale, Tinley Park Police. "But it seemed like they had been in the water for a good amount of time."
Officer Borrowdale, Detective Stan Tencza and Officer Dave Walker responded to the scene and first tried to throw the girls a rope.
"The girls would not reach for the rope or let go of the ice, at which time we had to make a determination whether to go in after them or wait for fire and rescue," Detective Tencza said.
"The three officers then went in the water and made their way out to the girls and formed a human chain and dragged them back out," Chief Neubauer said.
The girls were in the frigid waters for about seven minutes and were taken to a south suburban hospital as a precaution.
"It's great that they're okay. It was a good team effort by Officer Borrowdale and Officer Walker and myself," Tencza said.
"It's just not safe to walk on ice, period," said Neubauer. "You just never know the depth of it and how much weight the ice is going to hold. It's just very, very dangerous."
Also responding to the scene was an off-duty Cook County Sheriff's Deputy who happened to live nearby.
The two girls have left the hospital and are back home.