OAKLAND — A 25-year-old Vallejo man was killed and three other men wounded in three East Oakland shootings Friday night and early Saturday, police said.

None of the shootings are related, authorities said.

The fatal shooting, which also left a 21-year-old Pittsburg man wounded, happened about 11:56 p.m. Friday in the 9700 block of Mountain Boulevard near Knowland Park.

Police said the two men were in a car when someone began shooting at them from outside. The Vallejo man died at the scene and the Pittsburg man was taken to a hospital where he was in stable condition Saturday.

Investigators are trying to determine why the two men were in Oakland as well as a motive for the shooting. No arrests have been made.

The killing is the 16th homicide investigated by Oakland police this year. Last year at this time police had investigated 24 homicides in the city.

About 1:37 a.m. Saturday a 41-year-old man was shot multiple times as he sat in a car with another person in the 600 block of Hegenberger Road. The other person was not injured.

They were able to drive to a hospital where the wounded man was in stable condition. A motive for the shooting has not been determined and no arrests have been made.

The other shooting happened about 10 p.m. Friday at a hotel in the 8400 block of Enterprise Way.

A 28-year-old man told police he was standing outside when he heard gunfire and saw he had been shot. He was taken to a hospital and was in stable condition. Police have not released a motive in the shooting and have not made any arrests.

Police and Crime Stoppers of Oakland are offering up to $15,000 in reward money for information leading to the arrest of the shooter in the Mountain Boulevard killing and up to $5,000 in reward money in the other shootings. Anyone with information may call police at 510-238-3821 or 510-238-3426 or Crime Stoppers at 510-777-8572.

Check back for updates.