On Lookout Mountain, 12 miles west of Denver, Colorado, there is a shrine dedicated to Mother Cabrini, the first American saint. Her shrine overlooks the city of Denver; it is a peaceful, tranquil place. But on the morning of April 7th, 1984, a man leaving the shrine's grounds noticed a blue Buick parked on the roadside. The driver's window was shattered and the man decided to take a closer look. Inside the vehicle, he noticed a body, riddled with bullet wounds. The dead man was Mark Groezinger, a 29-year-old concrete cutter from the nearby town of Golden. According to his wife Judy, Mark had no known enemies:

"I don't think anyone disliked him. He was a very nice guy. He'd help you do anything and he was kind of shy, but for a friend, you know he was a real good friend to people."

The Jefferson County Sheriff's Department found that Mark had been shot repeatedly, in a manner that seemed obsessive. No trace of the murder weapon was found at the crime scene. However, investigators did find a paper bag filled with .38 caliber bullets on the right front floorboard of the car. Numerous shell casings were found both inside and outside the vehicle, suggesting the gun was reloaded at least twice during the shooting.

According to Lieutenant John Dunow of the Jefferson County Sheriff's Department, other intriguing clues were also found at the crime scene:

"We recovered the wallet, with his driver's licens and money he had in it. So we basically ruled out a robbery. But the thing that really was strange is the car keys were missing. And if there was a robbery, they would've taken the wallet and left the car keys."

According to Lieutenant Dunow, Mark's murder appeared to be a crime of passion:

"Well taking into consideration the number of bullets that were fired into Mark's body, it's clear to us that this is a killing of… rage, of fury, of hate, revenge."

Sheriff's Department investigators brought Mark's wife, Judy, in for questioning. Judy said that around 6:30 PM on the night Mark was killed, they had eaten dinner at a local restaurant with a friend. According to Judy, Mark wanted to go out, but she wasn't feeling well. Judy said Mark took her home around 8:00 PM. Her friend decided to keep her company at the house.

As Lieutenant Dunow investigated the case, he found several discrepancies in Judy Groezinger's story:

"Judy indicated that they went back to their residence at approximately eight o'clock and then Mark left to shoot pool. But we contacted people that were going up to the shrine to a wedding rehearsal that evening. They told us that they observed Mark's car there by the gate at 8:00 PM. So we have a problem there with that story."

Despite an extensive search of the entire area around the Mother Cabrini Shrine, investigators were not been able to locate a murder weapon to match the .38's shells. When Lieutenant Dunow ran a check on all recent .38 purchases in the Denver area, he recognized one name—Judy Groezinger:

"She had purchased the weapon in Denver at a pawnshop three days prior to Mark's death. And we asked her why she didn't tell us this initially and she said she forgot."

But according to Judy, it was her husband who told her to purchase the gun:

"Mark came home one day and he asked me if I could go to the pawn shop the next day and buy a gun for somebody and I asked him why the person didn't buy it themselves. He said they were just a little underage or something of that sort. So, I went down to Denver and I looked around and picked out the kind of gun he wanted: a .38."

Lieutenant Dennis Potter was another lead investigator on the case. He immediately questioned the managers of the pawn shop:

"The proprietors of the pawnshop that we talked to, were very adamant about the fact that there was a man with Judy Groezinger in that pawn shop that day. While she was picking out this gun, she called this male subject over to her and said words to the effect of, what about this one, do you like this one. Those type of words."

Then, according to Lieutenant Potter, another major discrepancy in Judy's story surfaced:

"Part of Judy's story was that after she and Mark finished dinner, they drove to a liquor store near their residence to buy a bottle of whiskey. We later contacted the person who was on duty that night in the liquor store. The lady says, ' I know Mark personally and I know Judy. And no Mark did not come in and buy whiskey that particular night.' That person told us Judy came into the liquor store at a later time with another man, matching the description of the man that Judy was with at the pawn shop. So we have two locations where Judy was seen with the same unidentified man. One at the pawn shop and the other at the liquor store."

In Mark's car, investigators found evidence that someone had stopped at a liquor store on the night Mark died. They found a six-pack of beer, but the receipt showed it was purchased from a different store than the one Judy named.

The murder of Mark Groezinger seemed to raise nothing but unanswered questions. Why had he been at the shrine, such an isolated, out-of-the-way location? And who had a motive for killing him? All investigators knew was that he was shot from the passenger side of his car and that his murder had all the earmarks of a crime of passion.

Without any clear leads, investigators brought in the only person who could verify Judy's alibi—the friend who had stayed with her after Mark dropped her off at home. She said she had watched TV with Judy until around midnight, then slept over on the couch. But according to Lieutenant Potter, rumors about the two women began to surface, casting suspicion on the friend's credibility as a witness:

"We interviewed friends and acquaintances and more than one acquaintance said that the relationship was more than just friends."

The day after Mark's murder, Judy's friend moved in with her. After living together for a few years they bought a house. However, according to Lieutenant Potter, investigators still don't have enough concrete evidence to charge Judy Groezinger with murder:

"We have no… evidence to place her there that night in that car. All we have is circumstantial evidence that indicates that she may be deceitful in some of her statements. We just don't know."

The murder of Mark Groezinger is a case filled with loose ends which may never be completely tied together. Throughout all of it, Judy Groezinger has maintained her innocence. She even took a lie detector test, which supported her story. But the discrepancies remain, and Judy Groezinger is still considered a person of interest. All that is known for certain is that Mark's killer is a free man… or woman.