Police don't know if the same person is responsible and in fact, they say it is probably not. They say the attacker in Monday night's assault appears to have a different motive than in the previous assaults that have taken place near Lake Merritt. Regardless, police are still warning women to be aware.
The lake has a reputation for being one of Oakland's safest neighborhoods, but a string of sexual assaults has some women rethinking their exercise routines around Lake Merritt.
"I'm going to make a habit of doing it around this time [dusk], or earlier or with a mate, a companion," said Nikki Decote from Oakland.
In Monday night's attack, the victim was walking home around 10 p.m. Police a say a man followed her into her apartment building and then sexually assaulted and brutally beat her.
"It was within the apartment complex, but not inside of her unit. So in the common area of the apartment complex," said Oakland Police spokesperson Ofc. Holly Joshi.
It is the fourth sexual assault since September in Oakland's usually quiet Lake Merritt neighborhood. Monday night's Jackson Street attack took place near the Chinatown border. On Jan. 18 a man attacked a woman in a residential area off Lakeshore Avenue as she walked home in the early evening. She was sexually assaulted and robbed. Twice on the same day in September, two more women were attacked and robbed near the lake. One in the 1400 block of Third Avenue and the other at East 18th Street and Lakeshore Avenue.
"We'll look into whether there's a connection, but at this time it does not appear the method of operation appear to be the same," said Joshi.
Police say the attacks may be purely coincidental. The most recent victim was not robbed. Non-rape sexual assaults are down 54 percent in Oakland. This time last year there were 61 -- 28 so far this year. The most recent attack took place just a few blocks from Laney College -- an area where students walk at all hours.
"It's pretty safe. You just have to take precautions and I think, walk in groups better than by yourself," said Asia Howard from Oakland.
"It's part of living in Oakland, you have to be on your guard," said Amelia Rais from Oakland.
Police have only a vague description of the suspect. He is described as an African-American man with medium complexion, 6 feet tall, wearing a dark long-sleeve t-shirt and a dark cap.
Anyone with information is asked to call the Oakland Police Department.