Early on in Boston Strangler, the two heroines — Boston Record American reporters Loretta McLaughlin (Keira Knightley) and Jean Cole (Carrie Coon) — receive a mountain of mail on their desks. Given the film’s genre, we’re prone to think the letters contain death threats or leads for the titular serial killer. However, they are messages from fellow women in fear who are grateful to the reporters for taking on the case so they may sleep peacefully again some night.

Hitting Hulu this week, the film will likely get lost in the endless sea of streaming true-crime content, but it deserves to shine this month as an empowering piece of women’s history. As far as true crime / journalism dramas go, Boston Strangler traverses well-worn territory. But it’s a good story well told.

Knightley stars as the reporter who beat her male counterparts to the punch in breaking the story of the titular terror in the 1960s. She found a connection between three victims — silk stockings tied around their necks like bows. Of course, the city’s police commissioner (Bill Camp) discredits her immediately, storming into the office of editor Jack MacLaine (Chris Cooper) the day McLaughlin’s first story hits doorsteps and dismissing her interviews with cops as acts of flirtation.

For the follow-up articles, Cole steps in to take some of heat off McLaughlin. While McLaughlin is a loose cannon, Cole is a calmer, more experienced reporter with a thicker skin. Personality-wise, they’re almost polar opposites, but Knightley and Coon poignantly convey the sisterhood they feel between each other and the victims they pledge to avenge.

Writer-director Matt Ruskin captures not only the era’s professional tension between men and women but the timeless tug-of-war between journalists and the justice system. From refusing to corroborate evidence to letting leads slip through the cracks, Boston’s police force was disturbingly out of order during the Strangler’s reign of terror. Every time Loretta locks eyes with a detective, you can cut the tension with a knife. Fortunately, to avoid portraying the entire police department as a black mass of incompetence, Ruskin throws in the character of Detective Conley (Alessandro Nivola), who is smart enough to swallow his pride and work with Loretta to catch the killer. The film recalls Zodiac when Conley describes how seemingly perfect but ultimately incorrect leads can leave you feeling like “the bottom has fallen out from under you.”

Boston Strangler goes on to borrow quite a bit from Zodiac in its exploration of obsession, but it’s nonetheless effective in knocking the wind out of you when its heroines pursue promising paths only to find dead ends.

The film probably could’ve done without reenactments of the titular killer’s murders. Ruskin should’ve taken one particular moment as a sign that the violence was gratuitous. The camera focuses on dripping bathwater as we hear a woman answer her door, get pushed back into her apartment and then beaten. The mundane dripping effectively contrasts with the mayhem in the background. But then we see her shoved into the water. It feels disruptive and out of place, like a studio executive’s note. Ruskin should’ve let Loretta and Jean tell the story there.

Except for a few such misguided moments, Boston Strangler matches the sensitivity of its heroines and does justice to their story, making it well worth watching now amid Women’s History Month.