While “Patriots Day” (Lionsgate) is an effective dramatization of the 2013 Boston Marathon bombing and aftermath, the film is also an unsparing portrayal of the events. Thus it can only be recommended for the sturdiest adult viewers.

Director and co-writer Peter Berg approaches the subject from multiple perspectives, predominantly that of fictional police Sgt. Tommy Saunders (Mark Wahlberg). Stationed at the finish line of the race, he is among the first responders to the chaos unleashed by radicalized Muslim brothers Tamerlan (Themo Melikidze) and Dzhokhar (Alex Wolff) Tsarnaev.

Among the victims profiled are husband and wife Patrick Downes (Christopher O’Shea) and Jessica Kensky (Rachel Brosnahan), and Chinese-born Dun Meng (Jimmy O. Yang), whom the murderous siblings carjacked and kidnapped. Meng’s courage helped foil their plans to carry out a further attack in New York.

Berg ratchets up the suspense as authorities scramble to identify and capture the fugitives before they can claim more casualties. And “Patriots Day” is clear about the need to oppose evil with love and decency, most forcefully expressed through a powerful monologue by Wahlberg’s character.

Although the treatment of it never descends to the exploitative or manipulative, the bloody carnage caused by the duo’s series of assaults is not kept off-screen. The grim sights are an unflinching presentation of reality.

The film contains disturbing and sometimes gruesome images of terrorist mayhem, considerable gore, drug use, a marital bedroom scene, several uses of profanity and pervasive rough and crude language. The Catholic News Service classification is L -- limited adult audience, films whose problematic content many adults would find troubling. The Motion Picture Association of America rating is R -- restricted. Under 17 requires accompanying parent or adult guardia