TAMPA, Fla. (AP) _ A man riding a city bus Saturday pulled a knife and stabbed the driver and two passengers, one fatally, then ran into a motel and stabbed a clerk before being shot dead by a sheriff's deputy, police said.

The assailant ''went berserk half a block after the bus started traveling,'' said Hillsborough County sheriff's spokesman Jack Espinosa.

The man joined about a dozen passengers aboard the bus just west of Tampa city limits, then pulled a knife with a 6-inch blade, said Espinosa.

The bus stopped near a shop where Hillsborough County reserve deputy sheriff David A. Rule was having his motorcycle repaired.

There, 14-year-old Clyde Russell, fatally stabbed, bloodied and hysterical, ran from the bus. The assailant fled on foot, ignoring Rule's shouted command to halt, and the reserve deputy took chase.

About a block later, the man ran into the office of Gene's Motel, where he knocked down Wava Gordon, 39, and knicked her several times. Clerk John Saunders, 41, rushed to her aid, and was stabbed in the neck and face, said Espinosa.

Rule arrived and fired two shots at the assailant, who ran towards Rule and then outside. Rule then fired three shots, killing the man, said Espinosa.

Russell died shortly after arriving at Tampa General Hospital, said nursing supervisor Kathy Flemister.

Bus driver Samuel Kelly, 30, was listed in very critical condition at Tampa General Hospital with a stab wound to the chest, said Espinosa.

Bus passenger Edward Kellner, 38, of Valrico was listed in critical stable condition at Brandon Community Hospital with a stab wound to the head.

Saunders, the motel clerk, was listed in stable condition at University Community Hospital. Ms. Gordon, who was kicked three or four times, was treated at the scene, Espinosa said.

Rule has been associated with the sheriff's office for 31/2 years, according to Espinosa, who said reserve officers are trained and certified by police standards and have power of arrest. They are unpaid.

Espinosa said police had not immediately identified the assailant.