MBTA Transit Police Sgt. Dic Donohue is retiring almost three years after being critically injured in the pursuit of the Boston Marathon bombers, according to WCVB.

Donohue said that he is still not 100 percent despite having fought through "pain and limitations" to be able to return to active duty.

"I did not want my career to be taken from me without a fight," he said to WCVB. "Unfortunately, I must now acknowledge the extent of my injuries and limitations. Physically, I cannot perform at 100 percent and must do what is right for myself, my co-workers, and my department. Therefore, I will step away from the job that I love so much."

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Donohue was in active pursuit of Tamerlan and Dzhokhar Tsarnaev as the brothers attempted to flee Boston after the bombings when he was injured severely. 

"I am forever grateful to my fellow first responders and the doctors who saved my life. There are too many to list, but they each have a special place in my heart," he told WCVB.

His decision to retire has come after living with almost constant pain in his legs, even with extensive rehabilitation. He said that the pain has made it impossible to fulfill his duties as a police sergeant.

"I am alive, and I have many plans for the future," he said. "If I had a choice, I would continue to serve as a police officer for decades to come, but those were not the cards I was dealt."

After retiring from the MBTA, he will teach criminal justice as an adjunct professor at a local college.