AURORA, Colo. – Emergency crews rescued a 15-year old boy who slipped beneath the surface of Cherry Creek Reservoir late Saturday.

The young teen and his family were at the lake, near the east boat ramp, when the incident happened.

Investigators say they received a 911 call around 7:42 p.m. indicating that a 15-year old had slipped into the water.

SMFR with West Metro Dive responding to person under water at Cherry Creek Res. Updates to follow pic.twitter.com/hLZAip0Opm — SouthMetroFireRescue (@SouthMetroPIO) July 23, 2017

South Metro Fire Rescue spokeswoman Kim Spuhler said they don't know whether the boy was on a water craft and fell off, or whether he was swimming or water skiing.

"We don't know the circumstances," she said.

Spuhler told Denver7 that crews on two rescue boats worked the surface of the lake, while dive team members went below and worked in a grid pattern.

Teams search from boats and under water. pic.twitter.com/blyDiAWmG4 — SouthMetroFireRescue (@SouthMetroPIO) July 23, 2017

"The biggest challenge was zero visibility," she said. "It was black water and they kept getting snagged on trash under the surface."

Spuhler said they found the victim in about 8 feet of water, 125 feet from shore.

"He was rescued at 8:45 and transported to Children's Hospital," she said. "We don't know his condition, but it was a rescue, not a recovery."

Thirty firefighters and two dive teams from three districts -- Cunningham, South Metro and West Metro -- took part in the rescue operation.

The name of the victim has not been released.