The emergency underneath the Niagara River that killed Buffalo, NY, police diver Officer Craig E. Lehner went from bad to worse in no more than 30 minutes.

Lehner was alone in the river during an underwater recovery training session when the tender cable that connected him to colleagues on land became snagged on an unknown object, three police sources told the Buffalo News Wednesday.

Team members on the Bird Island pier knew they had a serious problem when the line suddenly tightened. They let out more line and pulled it in different directions trying to free it and pull Lehner to the surface, said the sources who did not want to be identified because of the ongoing investigation.

When that did not work, two team members tethered themselves to Lehner's tender line and jumped in in an attempt to reach him some 25 feet under water. But the swift current, moving at 12 mph or faster, was too strong, and they were forced to cut themselves loose from the line and surface, the sources said.

Read full story at Buffalo News .