Boston police today released a surveillance photo taken when Rashad Lesley-Barnes was fatally stabbed on a Roxbury street, a killing that took place during a wave of violence in Boston last week that left five people dead.

Lesley-Barnes was 24 years old and riding on the MBTA’s 23 bus line when he got into an argument with a fellow passenger during the afternoon of Aug. 15. Lesley-Barnes was stabbed when he and his assailant were off the bus near 90 Warren St., according to police.

In the surveillance photo released today, the image shows a man wearing sunglasses with his right arm raised in a stabbing motion.

It marks the second time police have released surveillance photos of the man they call a “person of interest’’ in Lesley-Barnes’ murder. Police said the man boarded the 23 bus near School and Washington streets in Dorchester. A photo was also released showing the man when he entered the bus.

Last Friday, police released photos the “person of interest’’ taken by the camera on the 23 bus the day of murder.

According to his family and his most recent employer, Lesley-Barnes worked at Brigham and Women’s Hospital for six years, most recently as a patient transporter, and was attending Massasoit Community College with plans to become a chef.

Police asked anyone with information to contact homicide detectives at 617 343-4470 or to call the CrimeStoppers Tip Line at 1(800) 494-TIPS or text the word ‘TIP’ to CRIME (27463).

Jemald Allen, 34, was shot and killed in a Roslindale party and three women - Genevieve Philip, Sharrice Perkins, and Kristen Lartey, all 22 -- were murdered as they sat in a parked car on Harlem Street in Dorchester Aug. 12.

No arrests have been made in any of the murders, police said.