The heartless thug who fatally attacked a 77-year-old San Francisco Chronicle newspaper vendor in January has been apprehended, police said Monday.

Mark Anthony Cassell, 36, was arrested on suspicion of murder after cops in the Tenderloin recognized him from a department-wide crime bulletin. He was booked into the San Francisco County Jail

The attack that ended Dallas Ayres’ life occurred without warning in front of One Post St., near Market Street, about 11 a.m. on Jan. 28. The suspect wrapped his arms around Ayres’ waist, picked him up in the air and dropped him on the ground, police said. The suspect then fled.

Ayres, who worked as a newspaper vendor for about 30 years, died from his injuries on Feb. 21.

maldax@sfexaminer.com