Whether or not torture works is an incomplete question. The rest of it is, "works to do what?"
If the question is if torture works to get the truth out of people, the answer has been known for a long time and can be found in this addition to "The Pretty Complete Shakespeare Guide to Donald Trump": from The Merchant of Venice (1597), the protagonist Portia's response to a series of claims from a suitor to "live upon the rack" — an instrument of torture — until he has a chance to win her hand: "Ay, but I fear you speak upon the rack, / Where men enforced do speak anything" (3.2.25-33). Both more generally and more specifically, tortured men, women, and children will say what that they think will get the pain to stop, which may or not be true.
Torture, however, is effective in breaking people. The literary reference for that, as with torture producing all sorts of lies, is George Orwell's Nineteen Eighty-Four.
And if it seems extreme to talk here of the rack and the horrors of The Ministry of Love, note that Donald Trump has called for worse than waterboarding for prisoners who might have information on terrorism, so check out pretty much any annual report of Amnesty International for what worse than waterboarding includes. It includes for one regime I wrote for AI, the torturing of children in front of their parents in order to break the parents.
Note also that Mr. Trump threatened North Korea with "fire and fury like the world has never seen," and he made that threat on 8 August 2017, sandwiched between the anniversaries of the atomic bombings of Hiroshima and Nagasaki. Someone willing to contemplate ordering destruction worse than atomic bombings of cities — or the "conventional" fire-bombings of Tokyo or Dresden — should be taken seriously and literally on evils so much less extreme as crippling joint-by-joint a few dozen people on racks or killing off children by the ones and twos rather than by hundreds and thousands, as is inevitable with "fire and fury" exceeding that of the fairly recent past.