Police believe that one man is behind a series of brutal robberies and an attempted robbery on subways in Harlem since last week. Victims have suffered injuries ranging from a broken jaw to a punctured lung.

The first incident occurred last Tuesday, July 23rd, at around 9:30 p.m., when a 31-year-old man was approached by a man on a southbound C train near Saint Nicholas Avenue and West 125 Street. The man assaulted him and took his property. The victim had a broken jaw and eye socket. Here's video from that incident:

Two days later, on Thursday, July 25th, at 6:15 p.m., a 57-year-old man was approached by the suspect on a northbound C train near Frederick Douglass Boulevard and West 116 Street. The victim was robbed and attacked, left with a punctured lung and broken ribs.

On Friday, July 26th, at around 12:15 a.m., a 35-year-old man was approached by a suspect on the northbound platform of the C train at Frederick Douglass Boulevard and West 116 Street. The victim was attacked and robbed.

And yesterday, July 31st, at 4 p.m., a 27-year-old man was approached on a southbound A train at West 110th Street and Cathedral Parkway. He was also assaulted and robbed; he went to the hospital with facial injuries.

Anyone with information regarding these incidents is asked to call Crime Stoppers at 1-800-577-TIPS (8477). The public can also submit tips by logging onto the Crime Stoppers website at WWW.NYPDCRIMESTOPPERS.COM or by texting their tips to 274637 (CRIMES) then enter TIP577. All calls are strictly confidential.