BERWICK – The attorney for a 26-year-old motorist accused of leaving the scene of an accident in Berwick that killed a pedestrian says his client is mentally retarded.

Jason Brooks of Saco is free on bail on the felony charge arising from the May 27 death of Deborah Archer, who was struck by a van while walking her dogs along Route 9 near her home.

Brooks’ attorney, Walter Smith, said he informed state police that Brooks has mental retardation and he will present prosecutors with school records from Thornton Academy that will prove it.

According to a police affidavit, Brooks told police he “had a bad pain in his head” and looked away from the road when he hit Archer. Instead of stopping his van, he drove to Somersworth, N.H., where he called his father, who picked him up and drove him back to their Saco home. The father, Gordon Brooks, has been charged with hindering apprehension.