(CNN) -- Police in Baltimore have made a second arrest in a violent robbery that left a man battered and stripped of his clothes last month while onlookers laughed and did nothing to help.
The beating on March 18 made national news after much of it was caught on video and posted on the Internet.
The video also helped authorities identify suspects. On Monday, police said they arrested Shayona Davis, 20, for her involvement in the attack.
Another 20-year-old, Aaron Parson, has already been charged with multiple counts of robbery, theft and reckless endangerment, police said.
Authorities are looking for two more people, ages 18 and 21.
According to a police report, the 31-year-old victim from Virginia was headed to his hotel from a downtown Baltimore club when he was attacked.
The man, who had been drinking, told police he could not recall exactly what happened. However, the video fills in the blanks.
In it, a man is seen standing unsteadily against a row of mailboxes near the city courthouse.
A crowd starts to gather and women dance suggestively against him. Someone notices his watch and a hand seems to grab something from one of his front pockets.
He pursues the supposed thief and is punched in the face. The man falls over backward and his head hits the sidewalk so hard it can be heard on the video.
"Smackdown!" someone yells.
His pockets are rifled and his clothes pulled off. Some people can be heard laughing, and no one comes to his aid.
According to the police report, the man lost his Tag Heuer watch, which he valued at $1,300, his iPhone and car key.
CNN's Dugald McConnell contributed to this report.