Maryland correction officials have suspended and demoted three correctional officers who were involved in an incident last week in which a law student allegedly was assaulted during a traffic dispute.

The three were suspended without pay on Monday for 15 days and demoted from rank two correctional officers to rank one, according to Howard N. Lyles, acting assistant corrections commissioner for operations. The demotion will cut their pay from $13,065 a year to $9,850.

Lyles said the three - Frederick A. Pinder, 46: Roy C. Milner, 30, and Alvin J. Jackson, 30, all of Baltimore - were found to have violated state correctional regulations against misconduct and breaching security for leaving a corrections department bus with six prisoners aboard to "fight" 24-year-old Gerald Krizan, a University of Maryland law student.

The three officers are scheduled to stand trial in Baltimore Aug. 10 on criminal assault charges in connection with the incident.

The incident took place July 19 as the guards were returnign to the Maryland State Pentientiary in Baltimore after dropping a number of prisoners offat a correctional facility in Jessup, Md.

According to Lyles, the prison bus tried to pass Krizan's white convertible sports car on the Baltimore-Washington Parkway but it "could not muster enough speed to pass" and had to resume position behind the sports car when the parkway narrowed.

Krizan said that when the bus tried to pass him a second time, its door was open and the driver was shouting obscentities at him and someone threw something "that almost hit me in the head and bounced in and out of my car."

Krizan said he retaliated by throwing a paper cup half filled with ice and soft drink through the door of the bus, striking its driver.

The bus then chased the car, "with both vehicles bobbing and weaving in and out of traffic," according to Lyles, until both stopped at a traffic light just inside the Baltimore city limits.

At that point, Lyles said, the three corrections officers aboard the bus left their vehicle, which had six prisoners aboard, and got in the "fight" with Krizan.

Krizan said he was struck in the head between 15 and 20 times by two guards while the third pointed a shotgun at him. Krizan was treated at a hospital for cuts and bruises.

Lyles said the officers denied intending to use the shotgun on Krizan. He said they explained their behaviour by saying they lost their tempers while arguing with the law student.

"The Division of Corrections regrets that such an unfortunate incident happened and would hope that the public does not indict all corrections officers as a result of the conduct of these three," Lyles said.