This week, for the second time in a year, a person in a Philadelphia transit station after hours died an unnatural death.

A man in his 30s, possibly homeless, was fatally stabbed in Jefferson Station before dawn Thursday. In November, a teenage runaway was burned to death, likely by electrocution, in the middle of the night while on the top of a train at the same station.

Thursday's brutal 3 a.m. stabbing on a platform, which left blood through three floors of the subway and railroad hub, was caught on camera but remains unsolved, though law enforcement officials say they believe they have identified a person of interest. Both men involved in the altercation had told police in the past they were homeless, law enforcement reported, and they appeared to have known each other.

The stabbing and last year's death highlight a challenge for SEPTA police: balancing security with compassion for the city's indigent.

The incidents also highlight the reality that risk and the potential for violence are constant companions for people without a home. There are predators on city streets after storefronts and apartment windows go dark, said people who are homeless. They are often the prey, and vulnerability is a liability, they said.

>>READ MORE: After a killing, a meeting in Suburban Station's 'Living Room' for our city's most vulnerable

"It's a little bit more dangerous for the females as opposed to the males," said Rohman Griffin, 39, who has spent nights in Suburban Station. "If they're asleep, anybody could run up on them or do anything to them."

"We usually try to stay in groups," added Lisa Velasquez, 38, who was with Griffin at Suburban Station Friday afternoon.

Also at risk are elderly and mentally ill people, Griffin said. A homeless person has a 14 to 21 percent risk of being a victim of violence, a 2014 study by the National Health Care for the Homeless Council found, compared with 2 percent of the general population. Homeless women with mental health issues have a 97 percent chance of being a victim of violence in their lifetime, according to the National Sexual Violence Resource Center.

About 5,700 in Philadelphia live either on the street or in shelters or temporary housing

People stay in the stations, rather than at shelters, for many reasons.

"There are people who are homeless, addicted, or suffering from mental health that do not want help," said Sister Mary Scullion, who runs the homeless relief organization Project HOME.

Griffin and Velasquez said some people who recently became homeless may not be aware of all the shelter options available.

Completely securing stations like Jefferson and Suburban is virtually impossible, said Thomas Nestel III, SEPTA's police chief. Fire code requires the doors to have push bars so they can open from the inside, so every night when the station is being shut down, typically around 1:30 a.m., people hide inside and reopen the doors to let others in. A few police patrol the stations overnight, Nestel said, but people looking for a safe place to stay overnight try to stay out of sight of officers.

That may have been why Raekwon Jones, 15, was on top of a train on Nov. 29, 2017, when he touched a part carrying 12,000 volts.

>>READ MORE: Teen found electrocuted on top of SEPTA train 'was just a good kid who ran' | Helen Ubiñas

Griffin said he spends nights in Suburban Station without expecting to get sleep. He just wants a place to be. From the time the station is closed to its reopening about 4 a.m., he changes locations to stay out of sight of the officers who pass through once an hour. Others try to find hiding places where they can rest.

"People go to the bathroom and get in the stall and sleep on the toilet," Griffin said.

SEPTA police are trained to evict people from the station after hours, Nestel said, and do so almost every night. They do not charge them with any offenses like trespassing, though.

"They're not hiding to vandalize; they're not hiding to steal," Nestel said. "They're hiding to find a safe place to sleep, and they know with our officer in the station it's a safe place."

Nestel declined to say specifically how many officers patrol each station overnight, citing concern for publicizing tactics, but said he did not expect to boost the number of officers in the station over the long term because of Thursday's killing.

"If there's a need for it, we will," he said, "but one incident doesn't create the need."

He said SEPTA police were increasing the number of people watching the feeds from security cameras in the stations, though, and were exploring the possibility of installing technology like motion sensors to help identify when people were in the station. He noted the overnight shift was typically one of the quietest for SEPTA police.

One man who has spent nights at Jefferson, Gerald Clark, 45, said he has never experienced problems there.

"I just lay down on a bench and go to sleep," he said.

He's been asked to leave by police once or twice, he said.

Others who stay in the stations say they don't always experience that calm.

"It's very unsafe," Griffin said. "You have people running through there all times of the night."

Velasquez had firsthand experience with the risks of living on the street. In October, about a month after she was released from prison on an assault charge, she was spending a night on the porch outside 30th Street Station when a man tried to sleep near her.

"He wanted to rape me so he put a gun to my head and choked me unconscious," she said, "and when I woke up I had my pants pulled down."

She never reported the incident, she said.