MINNEAPOLIS (WCCO) — Police are investigating after a child fell out of a third-story window of a Spring Park, Minn., highrise building.

Authorities say the incident occurred around 10:15 a.m. Sunday at a condominium called Lakeview Lofts when the child apparently pushed through the window screen.

“Anybody’s worse nightmare is to have a grandchild hurt like that,” said Barry Stensrud, a friend of the family whose child fell.

The windows were open on the cool summer morning as a 4-year-old boy and his sister played while visiting their grandparents.

“They were playing some sort of game at the time the accident occurred,” said Correy Farniok, the Orono Police chief.

Somehow the little boy pushed through the window screen and fell at least 20 feet. The ground below was a concrete sidewalk, surrounded by mulch and grass.

“At this time, we don’t believe he landed on the concrete,” Farniok said. “He just slightly missed the concrete.”

Where he fell may have saved him from far worse injures. A quick reaction from those who saw it happen also helped.

When first responders arrived, someone was already giving the boy CPR. The boy had a pulse and was breathing when he was airlifted to the hospital.

The boy is in critical, but stable condition at North Memorial Medical Center.

There are a few simple preventative measures parents can take to prevent such accidents. For instance, hardware stores sell window guards for as little as $10.