A man was stabbed to death early Thursday in SEPTA's Jefferson Station in Center City during what police called a "very violent struggle" that was caught on surveillance video.
The suspect, who also may have been injured in the fight, fled and is being sought.
The attack occurred about 3:05 a.m., on the platform for Tracks 1 and 2 in the B section of the underground station, officials said. The station is closed at that hour and no trains were running.
The victim, who had no identification and was believed to be homeless, was taken to Jefferson University Hospital, where he was pronounced dead at 4:16 a.m., police said. Authorities said the man appeared to be in his 30s.
Police Chief Inspector Scott Small said surveillance video showed the suspect stabbing the victim at least four times.
He said the crime scene covered three levels of the station, prompting police to close the 10th and Filbert Streets entrance for the investigation.
"There was a lot of blood," Small said.
The Regional Rail station was open for the morning rush hour, but one track was out of service. The station fully reopened around 10 a.m.
While the investigation was underway, section B was closed and all trains that board on Track 2 boarded on Track 1, SEPTA said.