Silver Spring-based Acorn Media Group has acquired a majority stake in the Agatha Christie literary estate, which includes a library of nearly 40 TV flicks, 19 plays and more than 80 novels — and, of course, puts it in business with Hercule Poirot and Miss Marple.

For an undisclosed sum, Acorn bought a 64 percent stake in Agatha Christie Ltd. — the co-production partner of ITV Studios, which produces dramas based on Christie’s works for its parent network in the United Kingdom.

The Christie family retains its 36 percent stake.

The British media company Chorion held the majority stake in Christie’s literary estate for nearly 14 years. But Chorion has been selling off brands since putting its assets up for sale last year to repay debts, as it went into the U.K. equivalent of Chapter 11.

(Chorion has also been home to such other beloved British literary brands as the Beatrix Potter literary estate.)

Chorion’s loss is Acorn’s gain. Since 2001, Acorn Media has been releasing on VHS, DVD and digital its TV-movie adaptations featuring the two most famous Christie characters. They rank among the company’s best-selling series of all time.

ITV network recently commissioned new episodes of “Poirot” and “Marple” that are scheduled to begin production this summer for broadcast in 2013 on ITV and PBS. Feature-film adaptations are also in development, Acorn said.

The Christie acquisition is another step in Acorn’s evolution into content ownership and television production.

In much the same way, Acorn bought the British crunchy-gravel franchise “Foyle’s War” in 2010 from UK production indie Greenlit Rights, which also went into so-called “administration.” That deal marked the first time Acorn had bought ownership rights to one of its British series.

“Foyle’s War” was one of Acorn’s top-selling franchises on DVD for many years; it last aired on PBS in May of ’10.

“Foyle’s War” — set during and after World War II in Hastings, on the south coast of England — stars Michael Kitchen as methodical Det. Christopher Foyle, a widower who, assisted by his driver, Samantha, catches criminals by taking advantage of the confusion created by the war.

Acorn announced last month that Kitchen was returning for three new episodes.

“We believe Acorn will be a great future partner for the Christie family and will continue to nurture and treasure this property,” Chorion said Thursday in the announcement of the Christie estate deal.

In the announcement, Acorn noted that Christie is the best-selling novelist of all time, with more than 2 billion copies sold — behind only the Bible and Shakespeare.