MARTINEZ -- The teen driver accused of killing a father and his 9-year-old daughter during a Saturday morning bike ride in April is expected to change his plea to guilty to felony vehicular manslaughter charges later this month, according to his attorney.

Peter Coleridge, the attorney for 17-year-old Concord resident David Rosen, requested a change of plea hearing for his client during a pretrial hearing in a Martinez courtroom Friday, telling a judge he was making the request "because we fully believe there will be a change of plea."

Rosen, who pleaded not guilty Aug. 24 to felony vehicular manslaughter charges and a misdemeanor charge of reckless driving causing great bodily injury, will be back in court Sept. 26. He was charged as a juvenile in connection with the April 7 deaths of 41-year-old Concord resident Solaiman Nuri and his 9-year-old daughter Hadessa. They were riding their bikes on a Treat Boulevard sidewalk, along with Hadessa's 12-year-old sister Hannah, when they were struck by an SUV. Hannah Nuri survived the collision.

Prosecutors accuse Rosen of losing control of his speeding vehicle and running it off the road.

Michael Cardoza, the Nuri family's attorney, said Friday that he expects Rosen to plead guilty, and that the Nuri family is hopeful that the maximum penalty for him will be enforced.

"The family obviously wanted him charged as an adult, but they also want to move forward," Cardoza said. "This would be as good a resolution as they could hope for."

Senior deputy District Attorney Dan Cabral has said that Rosen could be held in a Contra Costa County locked juvenile hall facility until he turns 21 if convicted. At that point, he'd have to be released.

On Friday, Cardoza said he was unaware if the anticipated new plea will come with any sentencing conditions, saying "it will be up to the judge." Coleridge declined to comment after the hearing.

The Nuri family advocated for Rosen to be tried as an adult, but Cabral said the Contra Costa District Attorney's Office was not able to do so based on the charges against Rosen.

Rick Hurd covers breaking news. Contact him at 925-945-4780 and follow him at Twitter.com/3rdERH.