SCRANTON, PA. -- Henry Barr, a former top aide to Attorney General Dick Thornburgh, lied about his cocaine use to obtain the federal job, a prosecutor said yesterday.

Assistant U.S. Attorney Gordon Zubrod, in his opening argument in Barr's cocaine-conspiracy trial, accused Barr, 47, of lying about drug use on a federal form and in an FBI interview when Barr worked as an assistant to Thornburgh in 1988.

Lying in the interview allowed Barr to obtain the job and receive "access to sensitive national security information," Zubrod told the jury.

Barr is being tried on two counts of making false statements, one of conspiring to use cocaine and one of using cocaine. Barr could face 12 years in jail and fines of $510,000.

Defense lawyer Charles Scarlata said former state prosecutor Richard Guida and others expected to testify against Barr lied to the government about their own drug use. Guida, cooperating with the government, pleaded guilty last year to one count of distributing cocaine.

Barr served as a top legal aide to then-governor Thornburgh in Pennsylvania from 1982 to 1986. He followed Thornburgh to Washington in September 1988, serving as Justice Department liaison to the Drug Enforcement Administration and other agencies. He left the department in May 1989.