Now in his third docudrama with director Peter Berg – after starring roles in “Lone Survivor” and “Deepwater Horizon” that showed less versatility than virtual interchangeability – Mark Wahlberg is not quite the hero of “Patriots Day.” Rather, he is one of many fungible moving parts that drive the story forward, like cogs in a well-oiled machine.

Part thriller, part police procedural and part documentary-style ticktock, Berg’s movie, which he wrote with Matt Cook and Joshua Zetumer, retells the tale of the massive manhunt for the Boston Marathon bombers.

The film uses Wahlberg’s Beantown flatfoot Tommy Saunders as the furrowed yet ruggedly handsome face of the army of law enforcement officers that was mobilized after two homemade bombs exploded near the finish line of the 2013 marathon, killing three spectators and injuring hundreds.

MOST READ ENTERTAINMENT NEWS THIS HOUR. Joining such real-life figures as FBI Special Agent Richard DesLauriers, Boston Police Commissioner Ed Davis, Watertown Police Sgt. Jeffrey Pugliese and Massachusetts Gov. Deval Patrick, Wahlberg renders the composite Saunders as a kind of Everycop, an entirely fictional yet serviceable storytelling device that helps viewers follow the furiously focused search for brothers Tamerlan and Dzhokhar Tsarnaev through its many convolutions.

“Patriots Day” starts slow and somewhat predictably, jumping between scenes that introduce us to Saunders, the bombers and some of their soon-to-be victims in the hours leading up to the race.

Not so for Wahlberg, whose work with Berg is starting to feel repetitive, even dull at this point.

Later, when the Tsarnaevs have fled to suburban Watertown, w they are briefly cornered by local cops in a frenzied barrage of bullets and pipe bombs, Tommy is on that scene as well, in hot pursuit.

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