Originally Published: 02 MAY 23 07:09 ET

Updated: 02 MAY 23 10:09 ET

By Tina Burnside, Cheri Mossburg and Dakin Andone, CNN

(CNN) -- Officials in Davis, California, have lifted an overnight shelter-in-place order after they were unable to find a suspect in a knife attack late Monday -- the third such incident following two fatal stabbings in less than a week near the campus of University of California, Davis.

The startling advice for students not to venture out followed the killings Saturday evening of a UC Davis senior and Thursday of a 50-year-old man at different parks near campus. About 40,000 students are enrolled at the public university in Davis, a city of some 68,000 people about a 20-minute drive west of the state capital, Sacramento.

Police received a call about the third stabbing at 11:46 p.m. Monday, according to a news release from the city, which said the attack "occurred in a known transient camp" around 2nd and L streets.

The female victim told police the suspect stabbed her more than once through a tent, the release said. She was taken to UC Davis Medical Center, where she was in critical condition.

Officers from the Davis Police Department did not locate the suspect after a "detailed search" overnight of downtown, the department said in a statement. The shelter-in-place order was being lifted, but residents were urged to "continue to be aware of your surroundings."

City officials described the suspect as a man with curly hair, a thin build and a light complexion between 5-foot-6 and -9 inches tall. He was wearing a black or blue sweatshirt, black pants with white stripes and was carrying a brown backpack.

"The suspect matches the description of previous stabbing incidents," campus police said early Tuesday as they announced the shelter-in-place alert shortly after the latest attack.

The suspect in Saturday's deadly knife attack is believed to be a "light-skinned male, possibly Hispanic," between 19 and 23 years old and between 5-foot-7 and -8 inches tall with long curly hair, city police in Davis, California, said Sunday in a news release.

The FBI has joined state and local law enforcement in a manhunt for the suspect.

Extra officers were being deployed to patrol around schools and parks, the Davis Police Department said Sunday, adding it "understands the uncertainty, fear and panic that is arising in the community."

"At this time, it is strongly recommended that the community remain vigilant, be aware of your surroundings, and call the Davis Police Department if anyone acting violent, suspicious or matching the description provided is seen," police said.

UC Davis student Brayden Chipman, a classmate of the victim in Saturday's killing, told CNN affiliate KCRA prior to the third stabbing that the rash of attacks was worrying.

"Definitely a bit concerning, because you never hear of this stuff happening here. It's seen as like a safe community," Chipman said. "It's just really sad that a lot of students are just now fearing for their lives."

Extra patrols also were being added on campus and the UC Davis Police Safe Rides Program, which offers free rides and walking escorts to students on campus after dark, would expand, UC Davis Chancellor Gary May announced Sunday, calling the student's death "deeply unsettling."

UC Davis Police announced Monday evening the school had enlisted additional personnel through a private Sacramento-based security firm.

A community mourns

Authorities Monday were still probing the deaths of UC Davis computer science major Karim Abou Najm at Sycamore Park and David Breaux at nearby Central Park. Tips had led to some arrests "on unrelated charges or outstanding warrants, although none of these individuals have been linked to the murders," city police said.

"Although there are common factors between these two brutal crimes, such as the brutal nature of the crimes and that the suspect likely used a knife, there are no known connections between the victims; investigators are still determining whether the incidents are linked," they said.

Abou Najm's family told KCRA the 20-year-old was coming home from an undergraduate award ceremony when he was killed.

"I want this to be his memory: a bundle of energy, a bundle of positivity," Majdi Abou Najm said of his son. "Someone who was full of ambition, proud of his roots, who just wanted to make this world a better place."

The computer science major had a bright future ahead of him, according to Chipman, one of his classmates, who said Abou Najm "had a lot of opportunities, research, internships."

"Someone got robbed of their future," Chipman told the affiliate. "It's just heartless, people doing things like that. Seeing someone that I know, it's just felt a little deeply. It's really sad."

Breaux was a fixture in the community known as "Compassion Guy," according to a statement from the mayor and City Council that said he regularly asked passersby about their views on compassion.

"The death of David Breaux is utterly and completely devastating," Davis Mayor Will Arnold said. "Many of us knew David. We talked with him. We shared in his vision for a kinder world. We connected on what it means to be human and humane."