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William Costello, accused serial rapist, ends his trial by killing himself

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In November 2012, we told you about the arrest of William Costello, a successful real estate broker with powerful political ties, on accusations of serial rape -- and the next month, he was linked to two more sex assaults.

This week, prosecutors finally began laying out their case against Costello, only to have a mistrial declared -- because Costello had apparently committed suicide. See photos, video and details below.

As we reported, the rape accusations against Costello, 49 -- a broker for Denver's Unique Properties with a reputation as a good father and ties to influential Democrats such as Colorado Governor Dick Lamm -- began with a very different crime.

On June 30, 2012, according to the first in a series of arrest affidavits on view below, a Denver Police rep was called to the King Soopers at 2810 Quebec Street on an assault report. There, the officer learned that an elderly man had been standing near the door collecting signatures for a pro-life petition. When he asked a customer to sign the sheet on his clipboard, the man, later identified as Costello, rejected this entreaty because of his belief in abortion. However, Costello is also said to have shouted several obscenities -- and when the petition collector told him he could "still go to heaven," he supposedly became even more exorcised, grabbing the clipboard in order to throw it to the ground and pushing him off his bike.

The fall broke the man's hip.

At that point, Costello fled the scene -- but a witness eyeballed his license plate, allowing the cops to track him down. When confronted, Costello is quoted as claiming that while angry words had been exchanged, he'd only grabbed the clipboard to prevent himself from being struck by it and denied that he'd given the man a shove. Instead, he insisted that the man had toppled of his own accord.

The officer didn't buy this explanation and arrested Costello on suspicion of second-degree assault of an at-risk adult.

The bust triggered the collection of a DNA sample -- and when personnel checked it against previously collected data, matches were reportedly found in a three separate cases.

The first incident took place in March 2008 and involved a thirteen-year-old girl who lived at the Denver Children's Home. She told an officer that she'd become upset with the personnel at the facility and had decided to run away. Shortly after reaching the intersection of East 16th Avenue and North Bellaire Street, she was approached by a dark blue, four-door sedan driven by a five-feet-ten-inch, 160 pound white male with short brown hair and blue eyes.

The man, who wore a black baseball cap, a red T-shirt and green shorts, was accompanied by a two-year-old boy in the back of the vehicle. He told the girl his name was Will, and asked if she wanted to hang out. She agreed and climbed into the vehicle, at which point he began to touch and penetrate her genitals. This went on for five minutes or so, after which the man told her he'd ejaculated.

He then told her he wanted to do it again, and she complied, reportedly because she feared for her safety -- and she had every reason to be afraid. Before he let her go, she said he opened his trunk and pulled out a black, semi-automatic handgun.

Continue to read more about the death of accused serial rapist William Costello, including photos, video and original documents. Afterward, an examination was conducted, and semen was found in the girl's panties -- presumably the source of the DNA that matched the sample taken from Costello after the June King Soopers assault.

For the second case, skip forward to August 2010, when a Denver Police officer was dispatched to 14400 East Colfax to meet with an Aurora cop with a 22-year-old woman identified as a sex-assault victim.

The woman said she'd been near the intersection of East Colfax and North Krameria Street when she was approached by a male in a black Mercedes. At that point, she asked him to take her through the drive-thru of a nearby Del Taco to get some food, since the indoor seating area was closed.

Once in the vehicle, the man drove southbound and began to fondle her breast. She asked him if he was a police officer, and he initially told her no, but the narrative quotes him as changing his tune shortly thereafter; he claimed he was "crooked" and told her she could "make some money."

This offer didn't appeal to the woman, who reportedly asked for him to take her back to where he'd picked her up. Instead, he asked what are characterized as "sexually explicit questions" before pulling over, sticking his hand down her pants and trying to penetrate her vagina. He then is accused of pulling his pants down, putting on a condom, grabbing the woman by the neck and hair and forcing her to give him oral sex. Shortly thereafter, the man is said to have forced the woman to remove her clothes and began raping her. The woman screamed and cried, especially after the condom broke, but the man continued with the sex act while choking her. He then dropped her off at a 7-Eleven next to the Del Taco, at which point she contacted police.

The description of the suspect this time around was a bit different from the 2008 case, but with some similarities: a white male in the five-seven range, with a shaved head and no facial hair. He was wearing a black baseball cap, a gray T-shirt and blue jeans. However, the DNA collected from vaginal and abdomen swabs also scored a strike with Costello.

Continue to read more about the death of accused serial rapist William Costello, including photos, video and original documents. Case number three took place on September 28, 2011. The arrest report quotes the 49-year-old victim as saying that she was waiting for a bus at West 32nd Avenue and North Federal Boulevard when a blue Mercedes pulled up with the passenger window down. The man inside told the woman he was a police officer; when he ordered her into the car, she reluctantly complied. They then drove to an area near West 45th Avenue and North Irving Street, where the suspect -- a bald white male of medium build wearing a baseball cap, a blue shirt and blue jeans -- exposed his penis and told her she either needed to have sex with him or she'd be going to jail.

The woman said she'd prefer the latter, but she wasn't given the choice. The affidavit notes that the man grabbed her by the back of the head and tried to force her to orally service him. She responded by fighting him off as best she could, but he overpowered her, held her down, licked her breasts, neck and lips and digitally penetrated her anus. At that point, she told him she'd provide him with oral sex, but when he climbed back into the driver's seat, she jumped out of the car, ran to a nearby home with a porch light and began asking for those inside to call the police. At that point, the suspect drove away.

Again, a rape kit was used, and again, male DNA was found on a swab that matched with Costello's.

The result of these discoveries? Costello was charged with two counts of second-degree kidnapping, two counts of sexual assault on a child, three counts of sexual assault and two counts of impersonating a peace officer. And the following month, Denver District Attorney's Office spokeswoman told us that "two other people came forward with information" that connected him to another pair of cases, bringing the total in which he was suspected to five. Charges were subsequently handed down in one of these last two incidents, dating to 2011.

In the end, Costello stood accused of eighteen felony counts, including sexual assault, sexual assault on a child and kidnapping. His trial got underway on Wednesday, but Costello failed to show up on day two.

Tracking him down wasn't difficult. Although he was free on bond, the DA's office notes that he had been required to wear a GPS ankle monitor -- and when word reached prosecutors that a death investigation was underway at 2890 Brighton Boulevard for a man wearing just such a device, the connection was made. A mistrial was declared shortly thereafter.

Authorities at the scene say Costello appeared to have taken his own life.

Afterward, Denver DA Mitch Morrissey released a statement, calling the development "a sad resolution to a case in which many people had waited years for justice." He added that Costello had a misdemeanor conviction in 2003, and had DNA been routinely collected at the time, he presumably would have been caught far earlier, before he'd victimized so many women.

Continue to see a larger version of Costello's booking photo, a 2012 CBS4 report, and the aforementioned affidavits.

William Costello Arrest Affidavits

Send your story tips to the author, Michael Roberts.

More from our Schmuck of the Week archive: "Robert Bruce, serial rapist and schmuck, has bride asking, Who the [Bleep] Did I Marry?"

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