A 57-year-old Windsor man was arrested Sunday on suspicion of slashing his son with a knife in a Safeway parking lot, Santa Rosa police officials said.

Thomas Allen Dunn was booked into the Sonoma County Jail on suspicion of making criminal threats and assault with a deadly weapon, Santa Rosa Police Sgt. John Cregan said.

A shopper at the grocery store on Marlow Road called 911 at 9:54 a.m. after he exited the story and saw a man lying on the ground yelling that he had been stabbed, Cregan said.

The injured man, 27-year-old Taylor Dunn, had lacerations on his palm and told police he had jumped out of a vehicle driven by his father after the attack, Cregan said. The younger Dunn told officers that he had prescriptions for a narcotic and other drugs and his father demanded he get more of the drugs from the pharmacy to give him, Cregan said.

The Dunns visited two pharmacies but couldn't get any additional prescriptions that day, which angered the elder Dunn, according to police.

Outside the Safeway in a vehicle, Thomas Alan Dunn threatened his son and tried to stab him in the stomach and in the scuffle and slashed his son's palm before he got out of the car, Cregan said. Paramedics treated Dunn's injuries at the scene.