A Laurel police officer was released from the hospital yesterday after being stabbed nine times Sunday night in a fight with a motorist on Interstate 70 in Howard County.

Joseph Thomas Jr., 30, a four-year officer, was sent home from the University of Maryland shock trauma unit in Baltimore yesterday afternoon after initially being listed in critical condition. He had been stabbed in the back, thigh, shoulder, arm and hand, police said.

The suspect in the case, Ronald David Thomas, 33, of Union Bridge in Carroll County, posted $25,000 bond yesterday, after being arrested Sunday night and charged with assault with intent to murder.

The fight, which occurred shortly before 8 p.m. just east of the Carroll County line, began as Ronald Thomas was driving a pickup truck behind the officer, who was off duty and was riding a motorcycle, police said.

As both men traveled west in the center lane, Ronald Thomas, who is not related to the officer, turned on his high-beam lights, apparently as a signal that he wanted to pass, said to Detective Thomas Martin of the Howard County police.

The off-duty officer, who was following his wife, didn't change lanes because of heavy traffic, Martin said.

Ronald Thomas then passed the officer, straddling the lane markings and forcing the officer to swerve away from him, Martin said.

About one-half mile farther, Joseph Thomas caught up to Ronald Thomas, and both men pulled over to the shoulder.

The detective said Joseph Thomas then flashed his badge, identified himself as a police officer and said something to the effect of, "Don't you know I could have you arrested?"

Ronald Thomas replied, "I don't care who you are," then reached into his back pocket, prompting the officer to pull his handgun, Martin said.

Joseph Thomas then put his gun away, and the men shoved each other and fell to the ground, the detective said. As they rolled on the ground, the officer didn't realize he was being stabbed until he grabbed Ronald Thomas's hand and felt the knife, Martin said.

The weapon was a folding Buck knife with a 3- to 3 1/2-inch blade, the detective said.

After the fight, Ronald Thomas dashed across the interstate, climbed a fence, and ran about one-half mile before stopping at a house to make a phone call, police said. Noticing that Ronald Thomas was bleeding, residents of the house called for an ambulance and police, who arrested him.

Ronald Thomas, who was cut several times, was taken to Howard County General Hospital and was released Sunday night.

Ronald Thomas could not be reached for comment. And Joseph Thomas declined to comment.