OAKLAND — Five men were shot to death in a 18-hour period Monday night and Tuesday in different parts of East Oakland, police said.

The shootings don’t appear related, and police so far haven’t established motives for any of them. No arrests have been made.

The most recent was a man shot at 2:45 p.m. Tuesday in the 1500 block of 57th Avenue. The 44-year-old man’s name has not been released, and there are few details on the killing.

Two of the victims were found shot to death about 6:15 a.m. Tuesday in a parked van in the 1600 block of 72nd Avenue, a residential area between International Boulevard and Orral Street, police said.

Those victims, two friends named Robert Dell Jr., 23, and Deshawn Sutton, 27, both of Oakland, were in Sutton’s green Dodge van when they were shot. Police said they were targeted but don’t have a motive and no arrests have been made.

The two killings follow two unrelated shooting deaths less than 90 minutes apart Monday night.

At 10:20 p.m., 26-year-old Herron A. Adams Jr., of Oakland, was shot and killed outside Two Star Market and Liquor Store at 2020 MacArthur Blvd., in the Dimond district. He had just purchased a bottle of wine and was walking to his car when he was shot. Adams then fell through a window of the store and died at the scene, police said.

The storefront was also hit by gunfire, but no one else was hurt.

Another homicide occurred at 8:56 p.m. Monday, when an 18-year-old man was shot and killed while he was sitting in his van parked outside of Harry’s Drive In Liquors at 9002 MacArthur Blvd. His name was not released pending notification of relatives.

On Tuesday, Herron Adams’ sister, Sandra Adams, said she did not know why her brother was killed but thinks a gang is responsible for his death.

“I’m so speechless,” the 20-year-old Hayward woman said, before breaking into tears. “My brother is gone. It just hurts. He has a 4-year-old son, and he just had another baby.”

She said her brother, who goes by the nickname “Whoppie, was the oldest of four siblings.

“He was more of a mentor and best friend to my other brothers,” Sandra Adams said. “I’m so sad. So hurt. I don’t know why this would happen.”

Her brother was released from jail about one month ago, and it wasn’t his first encounter with gunfire, she said. Before he went to jail, she said, someone shot at him at least once.

Police said a 23-year-old woman, who was also in the parking lot at Harry’s Drive In Liquors, was hit by gunfire. She went to a relative’s home on Brookdale Avenue where police were called. She was taken to a hospital and is expected to survive.

A car driven by a woman who had her 14-year-old daughter as a passenger was hit by the gunfire ï»¿while going westbound on MacArthur, police said. The two were not hit, but the car was damaged.

The woman drove to 73rd Avenue and Weld Street, where police were called.

The five killings brought the number of homicides in Oakland this year to 94. Last year at this time, there were 88 homicides in Oakland.

Police and Crime Stoppers of Oakland are offering up to $20,000 in reward money in the shooting at 90th and MacArthur and up to $10,000 in the Dimond district shooting. A reward of up to $10,000 is being offered in the killing on 57th Avenue. Anyone with information may call police at 510-238-3821, the at tip line at 510-773-2805 or Crime Stoppers at 510-777-8572 or 510-777-3211.

Reach Harry Harris at hharris@bayareanewsgroup.com. Follow him at Twitter.com/hharris15 Reach Natalie Neysa Alund at nalund@bayareanewsgroup.com. Follow her at Twitter.com/nataliealund. Reach Kristin J. Bender at kbender@bayareanewsgroup.com. Follow her at Twitter.com/kjbender.