U.S. prosecutors in Philadelphia have charged a tug pilot with involuntary manslaughter in a deadly crash last summer between a barge and a duck boat that killed two Hungarian students, and he has agreed to plead guilty.

Investigators say the tug pilot steering the barge, Matt Devlin, was repeatedly on his cell phone dealing with a family emergency as the duck boat sat stalled in the Delaware River.

The July 7, 2010, crash also sent 35 others aboard the duck boat into the busy shipping channel.

The charge comes weeks after the National Transportation Safety Board issued its findings on the crash. The agency found that Devlin was also surfing the Internet while at the helm.

Devlin's lawyer, Frank DeSimone, has said he wouldn't comment until the charges were announced.