A review of the crime scene, physical evidence, and statements, as well as a 15-minute boat ride by Kenosha County investigators, is credited for cracking a two-decades-old cold case that led to homicide charges being filed against a McHenry woman for killing her former husband in Wisconsin, court records show.
Roxanna Collins, 70, of McHenry, and John J. Viskocil, 70, of Genoa City, Wisconsin, are each facing homicide charges for killing David Vanderzee in 2003, investigators said in a Kenosha County court criminal complaint.
Collins has been released from jail on a $500,000 bond since being taken into custody in early June. Viskocil remains held in jail, court records show.
The criminal complaint obtained by the Lake & McHenry County Scanner shows detectives from the Kenosha County Sheriff’s Office responded to 9100 391 Avenue, in Genoa City, Wisconsin, on September 23, 2003, after Collins called 911 to report she came home to find her husband, David, dead on the floor.
Collins was married to David Vanderzee at that point, court records show, and was using the name Roxanna Vanderzee at the time. She has since remarried and now uses the last name of Collins.
Inside the house, Vanderzee was lying face down with his right arm under his body, and his left arm forward of his head, the complaint shows. There was also a large pool of blood under Vanderzee and police determined he was shot “execution style” in the back of the head 5 times.
The wallet of the victim was found inside the home, the complaint shows, and there was no sign of forced entry or defensive wounds on Vanderzee.
The Wisconsin State Crime Lab indicated bullet fragments recovered from the scene had similar characteristics to a .38 special/.357 magnum caliber revolvers, and an autopsy revealed two spent rounds were recovered in the head of the victim, according to the complaint.
Collins was interviewed by police, but refused to submit to a lie detector test at the time of the interview.
In the complaint, Collins told police she left work to go shopping at Gurnee Mills at 5:45 p.m., and she spoke to the victim on the phone at some point between 6:15 p.m. and 6:45 p.m.
She came home after 8 p.m. and saw David on the floor with blood by his head, according to the complaint. She claimed she became hysterical and grabbed the cordless phone from the wall and called 911.
She ran out of the house and made contact with her neighbors, the complaint shows, who later told police Collins ran over to their residence screaming that her husband was shot.
That statement to neighbors was the first mistake, authorities said in the complaint, as it was impossible to tell whether Vanderzee was shot or bludgeoned to death due to the amount of blood at the crime scene.
By telling neighbors he was shot, it clued investigators in that she may be complicit in the murder, authorities said
Viskocil told police that he was friends with the victim and visited the home that day, the complaint shows, but that he had gone fishing and not been around for the rest of the day.
Interviewed a couple of weeks later, Viskocil said he went to David’s at 2 p.m. but only stayed for 1 minute. He left, went home to wash and cover his boat, then went fishing by himself from 6 p.m. to 8 p.m., according to the complaint.
Viskocil also told police he changed his clothes after returning home from fishing by himself because he fell off the boat when he returned to the dock, the complaint shows.
He said he did so because his girlfriend at the time always made a fuss about him leaving a mess in his house.
In the complaint, Viskocil told police that he was shocked by the murder because the victim, “…is not stupid. He had loaded guns in the house. He never saw it coming.”
Viskocil said during the investigation years later that the victim was a large male and a Navy veteran, an avid hunter and had a wealth of knowledge of firearms and how to defend himself, the complaint shows.
Based on this, along with the shot placement in the back of his head, no signs of a struggle or fight, suggest that David knew who was inside his residence when he was murdered, according to the complaint.
Like Collins, Viskocil also refused to take a lie-detector test during interview sessions, saying he had to protect his rights, according to the complaint.
Police interviewed Viskocil’s previous live-in girlfriend in 2003, 2012 and 2025, and she stated Viskocil was not present when she got home at 6 p.m. the night of the murder. She stated Collins called the house shortly after, and they spoke for about ten minutes.
Viskocil came home shortly after the phone call, she said, but did not recall Viskocil coming home wet, the complaint shows.
She added 30 minutes after Viskocil came home, the complaint says, he received the call that David had been shot.
The complaint noted Viskocil told his girlfriend at the time the victim was shot, but that information was not public knowledge when he said it, the complaint shows.
Viskocil also told police Collins stayed the night with him and his girlfriend at their residence the night of the 2003 murder, according to the complaint.
Viskocil broke off the relationship with his girlfriend on the day of Vanderzee’s funeral because Viskocil told her he did not love her. The girlfriend also said she moved out of the house she lived in with Viskocil only weeks after the murder, but that some of Collins’ belongings had already been brought in, the complaint reads.
Detectives conducted a search warrant on Viskocil’s home a couple of weeks after the murder, and the complaint shows he told police Collins had been living with him for approximately one week.
Viskocil called Collins four times between 7:47 a.m. and 8:11 p.m. the day of the murder, while Collins called Viskocil 6 times between 7:46 a.m. and 7:36 the day of the murder, court records show.
According to the complaint, Viskocil admitted to police that the number of phone calls he shared with Collins the day of the murder and his alibi that he was fishing alone looked “suspicious.”
Viskocil asked detectives if they thought he killed David, the complaint shows, and he responded that things certainly appear to indicate that.
Viskocil told police, “If I was going to kill him I would have used these,” and held his two hands out.
Viskocil had a FOID card and was taken by police, the complaint shows, and they recovered a box of 32 long caliber bullets, a box of 38 special caliber semi-wadcutters, a box of 38 special caliber bullets, and an antique gun was also taken as evidence.
Viskocil also handed over two .38 caliber revolvers to the police in 2003, the complaint shows. Investigators said Viskocil never requested the guns back.
In April, cold case investigators used a pontoon boat to time the trip from Viskocil’s dock on Powers Lake to Lakeside Park near where the murder took place.
Police determined in the complaint that it took 10 minutes to boat from Viskocil’s dock to a nearby park where he could tie up his boat, then another 5 minutes to walk to the house.
In addition, the complaint said residents in the area wouldn’t question Viskocil walking through the neighborhood as he was a frequent visitor to the home where the victim and Collins lived.
Two interviews with Collins linked investigators to the case even further, the complaint reads.
Collins showed no emotion and appeared very nervous when talking with investigators in 2012 and again in 2025. She also never denied killing Vanderzee, nor did she state that she did not have an involvement in his death, the complaint reads.
On top of all of that, multiple people interviewed regarding the investigation said it appeared as if the two had been having an affair while Collins and Vanderzee were still married, the complaint reads.
Viskocil’s former girlfriend told police it appeared that the two defendants were having an affair after the woman caught Viskocil and Collins holding hands on the couch the morning after the murder. She added Collins had already moved some of her personal property into the home that she was moving out of in October of 2003, the complaint reads.
During a previous interview in 2003, Viskocil admitted Collins was a “very special person and they talk often.”
In addition, the girlfriend said that defendant Viskocil and the victim were friends before David began dating defendant Collins, and mentioned that Collins had been married several times before marrying the victim.
Neighbors told police Collins’ reaction to the murder was not sincere, adding in the court records that Collins was not crying when she was at their house and out in the street, and didn’t start crying until the detectives had been in the victim’s house for about 10 minutes.
Collins was interviewed at her home in McHenry, IL, on April 26, and police told Collins that they thought she helped plan the murder, court records show. Collins looked away, tried to stop the discussions and looked at investigators with a blank stare, the complaint reads.