Nhan Thai was a few steps from his front door when he was punched in the face and grabbed from behind. He felt a blow to his neck, his jacket was torn from his body and he was knocked to the pavement with a kick to his back.

Thai rolled over in time to see two black teenagers running off with his jacket and gym bag. He didn't see their faces and could tell police only that they were dark-skinned and young, probably 15 or 16. One wore an orange jacket or sweatshirt.

Thai's wallet, house keys, cellphone, iPod and camera were stolen in an attack that lasted only a couple of minutes but has had a lasting impact on his sense of security, so much so that he's altered his daily routine.

A disease investigator for Public Health — Seattle & King County, Thai, 29, has spent a lot of time working on the streets and inside the King County Jail. Even in those high-risk situations, "I was able to sense when it was not safe," he said.

The robbery was a different story. "The loss of security was huge ... I'm still trying to make sense of it. It took a toll on me," he said.

Thai was robbed while walking home from the Othello Light Rail station on Sept. 15, two months before Danny Vega, a 58-year-old hair stylist, was viciously beaten about a half-mile from where Thai was attacked.

Vega, who was robbed of his jacket, cellphone and keys on Nov. 15, died 12 days later at Harborview Medical Center. Seattle police have since released surveillance photos of three young, black men who are considered persons of interest in Vega's homicide investigation.

Vega's family has suggested Vega may have been targeted because he was openly gay. But Sgt. Sean Whitcomb said police don't know the motive for the beating and robbery, though they do know items were taken from Vega.

Vega, a prominent member of the city's Filipino community, was attacked from behind and beaten unconscious during an evening walk near South Othello Street and Martin Luther King Jr. Way South. When he woke up, he managed to walk to his home nearby, where his housemates called 911. Vega was disoriented and in so much pain that he could provide only vague descriptions of his assailants.

While there's no known connection between the attacks on Thai and Vega, there are similarities in geographic proximity, the items taken and the manner in which the robberies were committed.

"Robbery isn't theft — it's a violent crime," Whitcomb said. "This is intimidation, it's fear, it's violence and it's a serious deal."

According to Seattle police reports, there have been roughly 30 street robberies or attempted street robberies in South Seattle since Sept. 1, a number that includes the attacks on Thai and Vega. Though it's unknown if there's been an increase in South Seattle, Whitcomb said, robberies have dipped 3 percent citywide this year compared to 2010. Still, Seattle officers respond to an average of 110 robberies a month, he said.

In the South Seattle street robberies, some assailants have been armed with handguns or knives, while some used fists and feet.

While most victims weren't badly injured, a few required medical attention, including a man whose head was repeatedly smashed into the side of a building during a robbery Nov. 2 on Rainier Avenue South.

Wallets, cellphones, purses and bags were typically taken, though several victims' gold chains were snatched from their necks, and a couple of medical-marijuana patients were robbed immediately after purchasing pot, according to the reports.

Many of the victims reported being robbed by two or three black teenagers or young men. One police report from early September noted that "there are numerous gang members that loiter in the area of Rainier Avenue S and MLK Jr Way S on a daily basis."

Robbery detectives have launched undercover investigations into at least two jewelry stores along Martin Luther King Jr. Way South where they have recovered stolen gold jewelry and personal electronics, according to search warrants filed in King County Superior Court.

At one of the jewelry stores, police found Thai's cellphone and iPod, and returned the items to him, Thai said. The store owner has not been charged with a crime, court records show.

Around 8:30 p.m. on a Thursday in September, Thai — who works downtown and frequents a gym there — returned to his neighborhood in Seattle's Rainier Valley. Another man got off at the same station and walked about 10 paces ahead of Thai. The man eventually hung a right, and Thai turned left. The teens jumped him from behind moments later.

Thai, who lives with his mother, sister and aunt, said no one in the family got much sleep that night. They wedged chairs under door knobs and put sticks in their windows, worried the robbers would come back and get inside the house with Thai's stolen keys.

The next day, Thai stayed home from work while his locks were changed.

Looking back, Thai said the other man's presence on his walk home gave him a false sense of security.

"My guard was way down. I was completely not aware at all," he said.

Like Vega, Thai is openly gay. But he believes his size — he's 5 foot 2 and 125 pounds — made him a target, not his sexual orientation. He also thinks his assailants watched him, perhaps for days, because they seemed to know his routine and his route home.

Now, Thai comes home at a different time every day and sometimes takes a bus instead of light rail. He's gone door-to-door to warn his neighbors, and in the process has learned of other victims of street robberies.

He's still angry about Vega's death and doesn't want it to be seen as an isolated incident. Thai attended a recent community meeting with South Precinct police commanders. Vega's relatives were there, too.

"I saw his family and my heart just broke to pieces," Thai said. "I could've been Danny, and it could've been my family sitting there."

Sara Jean Green: 206-515-5654 or sgreen@seattletimes.com