A police report on a car crash that killed two Southborough sisters says that the 17-year-old girl at the wheel of the vehicle appeared intoxicated and was playing a drinking game at a party with 15 or 20 other young people just before the accident.

The report, released yesterday by Northborough police hours after Governor Mitt Romney and Attorney General Thomas F. Reilly traded accusations over the politically charged case, quotes Northborough Police Chief Mark Leahy as telling prosecutors he believed his investigators had a case for what he described as ''allowing" a minor to consume alcohol.

Witnesses told police that Shauna Murphy, 17, brought vodka with her when she arrived at the Oct. 12 party with her sister, Meghan, 15, and a third teenager; the sisters died in an accident about 2 1/2 hours later. The report identifies the host of the party as Nathaniel Berberian, 20, of Northborough and says that it appeared he was ''in control of the house" where the party occurred and ''allowed underaged persons to drink."

A woman who identified herself as Berberian's mother said in a brief telephone interview yesterday that ''he did not supply any alcohol." Berberian and three witnesses also told police that he did not provide alcohol to the teenagers, according to the police report.