“Oh my God, now we’re all going to get a black eye,” was Jacki Mari’s first thought when she heard that a false tip from a psychic had led law enforcement officers on a fruitless search for a mass grave in East Texas on Tuesday night.

Ms. Mari, also known as Sherlockjackie, has, by her own reckoning, helped solve more than 400 murders and missing persons cases around the world — all without leaving her office outside Chicago. Her own psychic powers — she calls it “extrasensory intelligence” — told her that the informant’s tip was spurious, Ms. Mari said, even before the news media frenzy over the search in Texas died down and the spokesman for the sheriff’s department confirmed that no bodies had been found in Hardin, northeast of Houston.

“My first feeling was that something did happen,” Ms. Mari said, “but I didn’t see a bunch of bodies laying around or dismembered.” Besides, she added, “I would never call the police department and say, ‘Hey, I’m a psychic and I know what’s what.’ ”

The psychic’s phone call to the Liberty County Sheriff’s Department — which summoned not only sheriff’s deputies but also F.B.I. agents, Texas Rangers, cadaver-sniffing dogs and an army of news media personnel — was only the latest milestone in a long and uneasy relationship between law enforcement agencies and people claiming extrasensory powers.