Police boats combed the banks of the Potomac River on Friday, moving slowly under rainy skies and scanning the shoreline as investigators sought clues into the midair collision that killed 67 people and raised questions about air traffic safety around the nation’s capital.

More than 40 bodies have been pulled from the Potomac River as a massive recovery effort continues following the deadliest aviation disaster in a generation.

• Cause of the collision: The exact cause remains unknown. Officials reported clear flight conditions as the jet, arriving from Kansas, was making a routine landing when the helicopter entered its path.
• Victims: The passengers included figure skaters, their coaches and family members returning from a development camp following the U.S. Figure Skating Championships. Marylanders, including Jesse Pitcher and decorated ice skater Alexandr “Sasha” Kirsanov, were also among those killed.