Mark Allen Hopkinson (October 8, 1949 – January 22, 1992) was a convicted proxy serial killer who was responsible for arranging the 1977 murders of Vincent Vehar, Beverly Vehar, and John Vehar, and the 1979 murder of Jeffrey Green, a key witness against him, in Wyoming. Hopkinson is the only person to have been executed by the state of Wyoming since the 1960s. Gerry Spence served as the special prosecutor who won the case against Hopkinson.

Hopkinson was sentenced to death specifically for Green's murder, the deciding factor being that he had arranged it from a federal prison in California, where he was serving time for trying to arrange the murder of another man in the state of Arizona. While on death row, Hopkinson allegedly tried to arrange additional murders.

Background Mark Hopkinson returned to his native home in the Bridger Valley area of southwest Wyoming some time in 1975. He had earlier left the Valley after accepting a football scholarship to the University of Arizona. While away, he was convicted on charges of delivering controlled substances in 1971. Shortly after his release from a federal prison, he reappeared in Wyoming.

Hopkinson–Roitz dispute Late in 1975, Hopkinson became embroiled in two legal disputes in which Vincent Vehar, an attorney, assumed something of an adversarial role. The first dispute arose between two families, the Hopkinsons and the Roitzes, over water rights. In 1974, Joe Hopkinson, Mark's father, began doing ground work for a trailer court, in the process covering a ditch carrying water to the Roitzes. The Roitzes consulted Vehar and, as a result, filed a lawsuit against Joe Hopkinson. Shortly after a judgment was entered in the Roitzes' favor, Mark Hopkinson returned to the Valley. Mark Hopkinson not only assumed control over the development of the trailer court, but also sought to have that judgment reversed on appeal.

In April 1976, Mark Hopkinson visited the Roitzes and asked them if they, together without any attorneys, could work out a settlement. When the Roitzes refused, Mark Hopkinson warned them that he could construct the trailer court in such a manner as to inconvenience them greatly. On May 6, 1976, Mark revisited the Roitzes and attacked 55-year-old Frank Roitz. After Mark was pulled away from Frank, Mark's father, Joe, armed with a hammer, arrived at the scene. The two men together then beat Frank Roitz. When the fracas was finally over, the Roitzes consulted with Vehar and decided to talk to the county attorney about pressing charges; however, the county attorney was Jim Phillips, who had been hired by Mark to appeal the original judgment. Phillips, acting in his official capacity, refused to file charges in the matter.

Water Board dispute Meanwhile, another dispute pitting Hopkinson against Vehar had begun to brew. In 1975, Joe Hopkinson had approached the Fort Bridger Sewer and Water Board, a client of Vehar, to see if he could get his proposed trailer court annexed to the sewer district. He wished to connect to the district for the usual $100 initial hookup fee. Before any official action could be taken, the Board was presented with a petition, signed by 95 percent of the district's membership, seeking to raise the fee. The Board conducted several public meetings in order to determine what it should charge to hook up the trailer court. After extensive negotiations between Mark's attorney, Phillips, and the District's attorney, Vehar, a contract was entered into on March 13, 1976, providing for the annexation of the Hopkinson property to the district and requiring the payment of a hookup fee of $300 per trailer.

Once the hookup had been completed, Mark announced that it was his intention not to pay the contract price. During the ensuing struggle in which the Board tried to force Mark to pay, various board members received threats from Mark. This resulted in the filing of a suit on January 28, 1977, by Vehar on behalf of the Board. The complaint filed not only sought to force Mark to pay the money due under the contract but also requested $50,000 in exemplary damages because of the threats made against the board members.

During 1976, Mark first hired Jeff Green as a carpenter to work on various projects. Green in turn introduced Mark to his friends Mike Hickey, an admitted alcoholic, and Jamey Hysell. Along with these friends, Green had engaged in several larcenies and burglaries in the area.

Murder of Kellie Wyckhuyse In June 1976, Jamey Hysell was arrested for possession of marijuana as a result of a statement made to the authorities by Kellie Wyckhuyse, a fifteen-year-old girl who had spent a night with him at his home. In retaliation, Hysell plotted with Mike Hickey to murder her.

In accordance with their plan, Hickey picked Kellie up on June 27, 1976, and took her to an isolated spot in the country where he was to meet Hysell. Hickey informed Kellie of their plan to kill her, and when Hysell failed to show, Hickey struck her on the head with a rock, killing her. He then cut out her genitals to take to Hysell as proof that the job was done, and buried her remains.

Earlier attempts Late in 1976, Mark Hopkinson first approached Harold James Taylor about "doing a job for him." During the course of their conversations, Hopkinson explained that the job involved assaulting a man in Evanston, Wyoming. An arrangement was made whereby in exchange for $200 Taylor agreed to perform the job. Hopkinson then offered Taylor photographs of Vincent Vehar, the intended victim, and explained that he was a lawyer who lived in Evanston. Before the job could be done, Mark came back to Taylor and stated that his people wanted Vincent Vehar killed. Taylor agreed to this but upped his price to $600; he received this money on December 19, 1976. Shortly thereafter Taylor announced that he would not murder Vincent Vehar.

In March or April 1977, Mark had a conversation with Kenny Near, a past president of the Sewer Board. During their talk Mark offered Near about $2,000 for testimony that the Sewer Board was acting in a vindictive manner towards the Hopkinsons. However, Near refused the offer.

Mark Hopkinson then turned to Jeff Green and Mike Hickey for ideas as to how to get rid of Vincent Vehar. Several plans were suggested, but none of them were carried through. It was also during this time period that Mark Hopkinson first learned that Mike Hickey had killed Kelly Wyckhuyse the previous summer.

On April 4, 1977, Jeff Green was caught with a bomb in his possession when he was stopped in Utah for speeding while driving Mark Hopkinson's car. He was on his way to Arizona in order to plant the bomb in the car of George Mariscal, a former gambling associate of Hopkinson who allegedly owed him $10,000, on behalf of Hopkinson. When Mark was informed of Green's plight, he drove to Utah with Hickey and bailed Green out. Hopkinson thereafter refused to further discuss his plans for Vincent Vehar with Jeff Green.

Planning It was during the next four months that Hopkinson asked Mike Hickey about various ideas to either kill William Roitz or Vincent Vehar. Hopkinson promised Hickey $2,000 plus expenses and help in covering up the Wyckhuyse murder, if he would take care of one of these two men. Hopkinson and Hickey made several trips to various locations in the area in order to plan how the murder should be executed. Finally, by the end of July, Hopkinson had concluded that it was Vehar who should be killed and that the best way to do it was to toss a bomb through a basement window of the Vehar home.

Hopkinson received notice during the first week in August that he would be deposed by Vehar in connection with the Sewer Board's lawsuit on August 9, 1977. On Saturday, August 6, when Hopkinson saw Hickey at approximately 6:00 P.M., he ordered him to bomb the Vehar home that night. Hickey then went to the local bar where he stayed until approximately 1:30 a.m. He was then driven out into the country for a liaison with a woman whom he had met at the bar. Afterwards, Hickey returned to the bar at approximately 2:30 A.M. in order to pick up his vehicle. Very drunk he drove home; once there, he discovered that the girlfriend with whom he lived had not returned. Hickey then finally decided to go do the job as Hopkinson had demanded.

The murder of the Vehars Hickey was seen by a highway patrolman who was investigating an accident on the Interstate heading toward Evanston, approximately 30 miles (50 km) away, at 2:45 a.m. He arrived in Evanston and examined the Vehar home. After making sure it was safe, he threw the bomb in the basement window and departed. At approximately 3:35 a.m., the bomb went off, destroying the Vehar house and killing Vincent Vehar, his wife Beverly, and his son John. Another son, Tony, was injured in the blast but survived. On his way back to the Valley, Hickey picked up a hitchhiker. The hitchhiker testified that this must have occurred sometime between 3:30 and 4:00 a.m. Around 4:30 a.m., Hickey found his girlfriend and they returned home.

After the Vehar bombing, Hopkinson decided it would be a good idea if he and Hickey were not seen together. As a result, Hickey rarely saw Hopkinson and was never paid the $2,000 that had been agreed upon.

Arrests Hickey visited California during the fall; while he was away things began to unravel. Jamey Hysell, at whose command Mike Hickey had killed Kellie Wyckhuyse, was questioned by the police about several larcenies. As leverage, he told them about Kellie's murder. Since Hickey had shown Hysell where the body was, Hysell was able to take authorities to the grave site where the body was found. Hysell also implicated Hickey and Green in several of the small burglaries. The police tracked Hickey down in California and asked him about his involvement in these matters. At the time he denied any connection whatsoever but promised to return to Wyoming shortly. After his arrival back in the state he was charged in the Wyckhuyse murder.

To save Hickey, Hopkinson came up with a plan whereby Hickey, Green and Hopkinson would all tell stories implicating Hysell. Eventually this led to the dropping of the murder charges against Hickey and the indictment of Hysell for the murder of Kellie Wyckhuyse. Nonetheless, Hickey did go to prison on burglary charges in the spring of 1978.

It was before and during Jamey Hysell's trial for the murder of Kellie Wyckhuyse in July 1978 that Jeff Green broke down and decided to tell the truth. He first implicated Hopkinson and Hickey in the Vehar matter and then later, out of fear that Hysell may be put to death, confessed that his statements incriminating Hysell were lies, and that, in fact, Hickey had committed the murder. Green also expressed fears about the repercussions that might befall him as a result of his betrayal of Hopkinson. Green's testimony led to the dismissal of the charges against Hysell. The news of Green's testimony hit the newspapers shortly thereafter. It was at this time that Hopkinson promised Green's sister that he would get Jeff.

Mariscal trial In March 1979, Hopkinson and Hickey were tried in the United States District Court in Cheyenne, Wyoming, on federal charges arising out of Green's April 1977 attempt to place a bomb in Mariscal's car. After Jeff Green had testified against him in the trial, Mark Hopkinson also promised Jennifer Butters that he would get Jeff. As a result of the trial, Hopkinson, but not Hickey, was convicted and sentenced to 10 years in prison. He was confined to the federal prison in Lompoc, California.

Murder of Jeff Green