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A suspect in a dark suit and beanie captured on video kicking a homeless man in the face in San Francisco has been linked to another savage attack on a member of the city’s most vulnerable population, authorities said Friday.

But unlike the May assault that left his 38-year-old victim severely injured but alive, Samuel Youmtoub’s victim in Chinatown one month earlier wasn’t so lucky, police said.

Workers along Joice Street, a small alley near the historic Cameron House and a block from Willie “Woo Woo” Wong Playground, found Quang Truong, 49, dead inside the large cardboard box where he slept, covered in blood from a massive head wound in the early-morning hours of April 15.

Police said they linked Youmtoub to the shocking Chinatown killing that came amid an alleged spree of violence from the 59-year-old suspect, described in court documents as a computer technician frustrated over the issue of homelessness in San Francisco.

Tenderloin Station is seeking your help to identify this aggravated assault suspect. Anyone who knows who this man is should call (415)575-4444 and reference SFPD case 180387174. Warning: Graphic Video pic.twitter.com/R30PSEXvCk — SFPD Tenderloin (@SFPDTenderloin) June 7, 2018

Youmtoub was linked to the bloody killing last month and arrested. He is in custody at Napa State Hospital, where he was transferred after a judge on Sept. 19 found him incompetent to assist in his own defense in his other assault case. Prosecutors have not filed murder charges against Youmtoub.

Advocates for the homeless in San Francisco expressed relief after hearing that police had made an arrest in Truong’s killing, one of several high-profile slayings of people sleeping on city streets in recent years.

“It’s great police are taking it so seriously,” said Jennifer Friedenbach, executive director of San Francisco’s Coalition on Homelessness. “It’s very frequent that people come into my office with bloodied faces and say someone came up and kicked them.”

Youmtoub was first arrested June 17 — 10 days after police at San Francisco’s Tenderloin Station released video of a man viciously kicking another man twice in the face as he lay on the sidewalk on May 24.

The victim was found lying in a pool of blood before being rushed to San Francisco General Hospital. Video of the unprovoked attack drew widespread attention amid San Francisco’s ongoing homeless crisis and was played on national newscasts.

Authorities soon accused Youmtoub of being responsible for two more attacks, including a beating that left a Muni passenger with a broken nose in the Mission in May, and an attack on a man at Yerba Buena Gardens in February that required the victim to get stitches.

Youmtoub has a lengthy criminal history, including previous arrests for assault and burglary.

His attorney, Deputy Public Defender Ilona Solomon, said she could not comment on the case.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky