A woman walking by herself was knocked to the ground and punched in the face early Tuesday -- the fourth such assault this month in the North Park neighborhood.



Police said they have no idea whether the case is connected to the startling string of attacks on women in the popular Uptown neighborhood.



The woman was walking in the area of 2700 block of Lincoln Avenue at 1 a.m. when she was knocked to the ground and punched, according to a news release from the San Diego Police Department. She lost consciousness.



She told police that when she regained consciousness, she was fully clothed and the suspect was gone.



Police do not have a suspect description.

News of the latest attack came Wednesday, the day after details of a third attempted sexual assault on June 11 were released. This one involved a man who knocked his victim to the ground but was scared off before he could complete his attack.



Investigators said it happened around 1 a.m. on June 11 in the 3900 block of 33rd Street.



A woman was walking alone in the area when she was attacked from behind by an unknown man who knocked her to the ground and attempted to force himself on her. Police said a vehicle drove down the street at that exact moment, which likely scared off the attacker.



The man was last seen fleeing westbound on University Avenue.



Though there is currently no suspect description in connection with this case, police did release two photos of a person of interest wanted for questioning, which can be seen below or here. The man’s image was captured on surveillance tape in the area right around the time of the attack.



Detectives are working to determine if this assault is related to two other attempted sexual assaults that occurred in North Park on June 17 and June 21. Both of the victims in those cases were also walking alone when they were attacked, police said.



The June 21 case involved a woman walking alone -- also in the 2700 block of Lincoln Avenue -- at around 9:40 p.m.



She told police she was hit from behind by two suspects, who then knocked her to the ground. One suspect tried to pull off her clothes, but she fought back. After yelling for help, the suspect ran off.



In the June 17 incident, a woman was walking in the 3200 block of Meade Avenue at around 11:30 p.m. when she was attacked by two unknown men. She also fought back and the suspects fled.



All four attacks remain under investigation and anyone with information should contact the SDPD Mid-City Division at (619) 516-3000 or Crime Stoppers at (888) 580-8477. SDPD Acting Lt. Mike Holden said he believes the suspect in the June 11 assault may very well be involved in the attacks that soon followed.



The series of attacks have left North Park residents and visitors on edge.



Though the nightlight continues late into the evening in the popular community, police are warning women to avoid walking alone and be on high alert in the area.



Serena Mann and her sister, Frances, frequent North Park almost every night. The news of the three assaults over the past two weeks is unsettling, especially since the sisters tend to stay out late on the weekends.



“It’s pretty scary. I’d like to be safe in a place I hang out a lot,” Serena told NBC 7.

The San Diego Police Department released some statistics showing the rate of sex crimes in the North Park area compared to previous years. Officials said that last year 3.3 percent of sex crimes reported throughout San Diego happened in North Park. This year, that figure is already at 3.8 percent, and it’s only June.