(AP Photo/Courtesy Golfmanna)

Golfers look into a sinkhole on March 8 that opened up under golfer Mark Mihal on the 14th hole of a golf course in Waterloo, Ill. Mihal was hoisted out safely with a rope.

ST. LOUIS - Suddenly being swallowed up by the earth on a golf course's fairway drove a wedge between Mark Mihal and a stellar round.

The 43-year-old mortgage broker was counting his blessings Tuesday and nursing a dislocated shoulder sustained four days earlier when he tumbled into an 18-foot deep sinkhole on the 14th hole of the Annbriar Golf Club near Waterloo, Ill., just southeast of St. Louis.

C.A. Schmidt / golfmanna.com via AP

Mark Mihal, 43, a mortgage broker, fell into a sinkhole during a golf outing on Friday.

Friends managed to hoist Mihal to safety with a rope after about 20 minutes. But the experience gave him quite a fright, particularly following the much-publicized recent death of a man in Florida who died when his bedroom fell into a sinkhole. That man's body hasn't been found.

"I feel lucky just to come out of it with a shoulder injury, falling that far and not knowing what I was going to hit," Mihal, from the St. Louis suburb of Creve Coeur, told The Associated Press before heading off to learn whether he'll need surgery. "It was absolutely crazy."

Mihal said it was a real downer on what had been a fine outing.

With winter finally nearing an end, "it was the first day to get to play in a long time," he said. "So I wasn't expecting too much."

Golfing with buddies, Mihal was waiting to hit his third shot, some 100 yards from the pin on the par 5, when he noticed a bathtub-looking indentation about knee deep just behind him on the fairway. At just one over par for the round, the golfer with a 6 handicap was on a roll.

Mihal remarked about how awkward it would be to hit out of the odd depression, and then walked over to give it a closer look and took one step onto it.

"It didn't look unstable," he said. "And then I was gone. I was just freefalling. It felt like forever, but it was just a second or two, and I didn't know what I was going to hit. And all I saw was darkness."

Friends 'thought it was some crazy magic trick'
His golfing buddies didn't see him vanish into the earth but noticed he wasn't visible, figuring he had tripped and fallen out of sight down a hill. But one of them heard Mihal's moans and went to investigate.

"He just thought it was some crazy magic trick or something," Mihal said.

Hardly.

Getting panicky and knowing his shoulder "was busted," Mihal assessed his dilemma in pitch darkness as he rested on a mound of mud, wondering if the ground would give way more and send him deeper into the pit.

"I was looking around, clinging to the mud pile, trying to see if there was a way out," he said. "At that point, I started yelling, "I need a ladder and a rope, and you guys need to get me out of here."'

A ladder that was hustled to the scene was too short, and Mihal's damaged shoulder crimped his ability to climb.

"At some point, I said, `I need to get out of here. Now,"' Mihal recalled.

One of his golf partners, a real-estate agent, made his way into the hole, converted his sweater into a splint for Mihal and tied a rope around his friend, who was pulled to safety.

"I felt fortunate I didn't break both legs, or worse," Mihal said.

While disturbing, such sinkholes aren't uncommon in southwestern Illinois, where old underground mines frequently cause the earth to settle. In Mihal's case, the sinkhole's culprit was subsurface limestone that dissolves from acidic rainwater, snowmelt and carbon dioxide, eventually causing the ground to collapse, said Sam Panno, a senior geochemist with the Illinois State Geological Survey.

That region "is riddled with sinkholes," with as many as 15,000 recorded, Panno said.

The one Mihal survived has him debating whether returning to Annbriar is a long shot.

"It's a great course. I love the course," Mihal said, having played Annbriar a couple dozen times over the past decade. "But I would have a tough time probably walking down that hole again."

The 20-year-old course proclaims on its website that "each year new golfers are tested by our challenging 18 holes of golf."

There's no mention of its newest - and most challenging - hole.

Slideshow: Striking sinkholes: Earth opens up

Luis Echeverria / AP

A look at some of the most amazing sinkholes around the world.

Launch slideshow

Three decades have passed since Robert and Goldie Huntbach were found tied up and shot to death in their Waterloo, Iowa, home, and no suspects were ever arrested in the elderly couple's murders -- until this week, when one of them voluntarily walked into police headquarters and confessed.

"There were a lot of suspects at the time that we looked into," Waterloo police captain Tim Pillack, who was working for the department when the Jan. 12, 1981 double homicide happened, told msnbc.com. "We just were never able to get enough probable cause against somebody to make an arrest."

The case eventually went cold. Then, on Tuesday, Jack Wendell Pursel showed up at the police station in this city of nearly 70,000 with something to say.

"Basically, he just wanted to talk to someone about it," Pillack said. "We had one of our investigators interview him, and he confessed to killing them."

Pursel, 66, told the investigator he had planned to rob and murder Robert Huntbach, 85, and Goldie Huntbach, 75. He gave details that only a person involved in the crime would have known, but Waterloo police didn't release what those were.

The homicide was grisly: Robert had been found in the couple's dining room, blindfolded, with a dish towel in his mouth, according to Waterloo Daily Courier archives. He had been hit with a blunt object. Goldie was in a hallway, blindfolded, with a clothespin on her nose, The Daily Courier said. An electric cattle prod had been discovered in the master bedroom, and Robert had injuries on his chest and wrists that may have come from the device.

It's unclear whether Pursel knew the Huntbachs, who were retired at the time of the killings. But he had been one of the suspects that Waterloo police interviewed early on in the case.

"From what we were able to find, he knew one of the victims' children or grandchildren -- I believe their grandchildren," Pillack told msnbc.com. "He was one of the suspects way back when that we looked into at the time."

Police have no idea what prompted Pursel, who is being held in the Black Hawk County Jail on two counts of murder in the first degree, to turn himself in now.

Pursel has not had a perfect record during the 31 years since he was first interviewed for the double homicide. He lived in the Waterloo area at the time of the murder, Pillack said, but for the last 15 or 20 years, he was living in South Gate, Calif.

"Before that, he was in prison [in California] for some type of sexual contact with an underage person," Pillack said.

The Huntbachs had two daughters and a son. Only one, daughter Barbara Beck, is still alive. A call from msnbc.com to Beck went unanswered on Friday. But Pillack said when he spoke with her on Thursday to share news of the confession, she was in a state of disbelief.

"She just wanted to make sure that we had the right person in jail," he said. "She wanted assurance that this wasn't going to continue on."

Pursel had an initial court appearance on Thursday, in which his $500,000 bond was increased to $1 million.

Pillack, who has worked for the Waterloo police department since 1979, said the 1981 double homicide was "a shock to community," and having Pursel turn himself in this many years later was totally unexpected.

"It's very unusual to have somebody confess to any crime, let alone a double homicide that happened 30 years ago," he said. "But we were happy to be able to say we solved the crime."

More content from msnbc.com and NBC News:

• Cities: Occupy protests cost taxpayers millions
• Plastic card makes landfall in Alaska after 33-year sea voyage
• Houston reporter fired for stripping files discrimination complaint
• Suspected kidnapper dead, 2 girls found unharmed
• Video: Pier collapses during prom photo shoot

Follow US News on msnbc.com on Twitter and Facebook