By Steve Tawa

PHILADELPHIA (CBS) — A SEPTA Transit officer has been cleared of any wrongdoing for tasing a man, who later died, last October during a struggle at a station on the Market-Frankford line in Kensington.

Transit Police Chief Thomas Nestel says his officer was assaulted and he was forced to use his taser stun gun, during an 8-minute close-quarters battle:

“It was determined that the officer’s actions were appropriate, and within the guidelines of departmental policy.”

Nestel says at first, the incident was unremarkable, as security video depicts the officer peacefully escorting a man out, as he was closing the gates for the night, at the Huntingdon Station. But moments later, that man, later identified as 24-year old Omar Lopez, got into an argument with a second man. Nestel says when the officer interceded, Lopez turned on the officer.

Street level video showed their prolonged confrontation, as the officer tried wrestling moves on his attacker, and finally pulled out and used his taser gun, while trying to radio for help.

After Lopez was handcuffed and while being transported to the hospital, he became unresponsive, and later died. An autopsy disclosed Lopez’s death was accidental, due to a PCP drug overdose.

Nestel says the SEPTA report has no bearing on a separate investigation by Philadelphia Police:

“And that criminal investigation will be forwarded to the district attorney on a decision regarding whether criminal charges should be filed against the officer. That’s independent of this.”

Authorities are not releasing the name of the officer, because of a death threat, made on the internet.

“Somebody wanted to ‘take out the officer.’ That person posted an image of an AR-15 semi-automatic assault rifle,” Nestel said.

Nestel says they arrested a man and charged him with making terrorist threats and harassment.

As a result of the incident, SEPTA is introducing GPS tracking of equipment and officers. During the struggle, responding officers could not pin down his location.

A sergeant with the Transit Police was disciplined for failing to have Lopez transported to the closest hospital. Going forward, its communications center will verify that a transport is going to the closest hospital.