it was loosely based on the real life education of father gary thomas, the official exorcist of the diocese california. >> how do you know that someone is possessed by a demon rather than just someone under tremendous psychological strain? >> there are specific signs. for example, if a person has an aversion to walking into a church and not being able to view a crucifix or an image of christ. another sign could be if a person possesses a competency in a language they otherwise couldn't speak. >> father thomas was selected by the church for special training in rome to battle dark spirits. but the practices attracts its fair share of amateurs. like this phoenix trio dubbed the teenage "nightline" q;v interviewed in 2012. >> looking at eyes you can see that evil thrown back at you. when a demon comes into someone, it's desire is to steal, kill and destroy that person's destiny and life. >> armed with crosses, bibles and holy water, they claim to summon demons alongside their fearless leader. >> get your hands off me. >> at the school you walk away with no doubts whatsoever. >> rev land larson

the score exorcist to be honest with you. >> time to cruise. hope it's clean. >> reporter: which brings us back to our cruise. my team armed with this official bacteria meter. and, oh, yes, test swabs. >> that looks pretty dirty already. >> reporter: let's head right to the action. the food. everyone loves the self-serve frozen yoeg artgurt and look at everyone touching the handle. but good news, when we swab them, the handles come back totally clean. then we go to dinner and check the menu. that's clean too. >> clean. >> it's clean. we'll continue eating here. >> good. >> reporter: next, we try our luck at the casino. the blackjack. the slots. the jackpot of germs. we put our swab into the meter. health experts say any reading over 100 is a fail. >> that slot handle, look at that. 373, it is filthy. yet another reason not to gamble all your money away. >> reporter: same problem on the views ship's elevate rz. the buttons? 370 teeming with bacteria. we shared our results with e.r. doctor robert bladder. >> it's an island in the sea, everyone is working together, eating together, putting them at risk of passing infections to one another. >> reporter: okay ma

the exorcist to be honest with you. >> time to cruise. hope it's clean. >> reporter: which brings us back to our cruise. >> got it. >> reporter: my team armed thinks with official bacteria meter, and, oh yes. test swabs. >> that looks pretty dirty already. >> reporter: let's head right to the action. the food. everyone loves the self-serve frozen yogurt and look at everyone touching the handle. but good news. when we swabbed them the handles come back -- totally clean. then we go to dinner and check the menu. that's clean, too. >> it's clean. >> it's clean. >> we can continue eating here. >> good. >> reporter: next we try our luck at the casino. the blackjack. the slots. the jackpot of germs? we put our swab into the meter. health experts say, any reading over 100 is a fail. >> that's slot handle. look at this. 373. it is filthy. another reason not to gimble all your money away. >> reporter: same problem on the cruise ship's elevators. bunts -- 370. teeming with bacteria. we shared results with e.r. doctor. >> cruising are like an island in the sea. essentially everyone is living together working together eating together putting them at risk for passing infecti

the exorcist to be honest. >> time to cruise. hope it's clean. >> that are brings us back to our cruise. my team armed with this official bacteria meter.ead to the action. the food. everyone loves the self serve frozen yogurt and look at everyone touching the handle. good news. when we swabbed them the handles come back totally clean. then ghee to dinner and check the menu. that's clean too. >> we will continue eating here. >> next we try our luck at the casino. the black jack. the jackpot of germs? we put our swab into the meter and health experts say any reading over 100 is a fail. >> that slot handle look at this. 373. it is filthy. another reason not to gamble your money away. >> the same on the elevators. the buttons are 370, teaming with bacteria. we shared results with the er doctor. >> they are like an island in the sea. everyone is living together working together eating together and putting them at risk for infection. >> maybe we will get relief by the pool. don't sit down yet. we swabbed down this lounge share, a whopping 773, more than seven times higher than the acceptable limit. if you think that's bad, just wait until yo