Three years after her disappearance, police charged Michael Horvath, 49, in the death and kidnapping of his co-worker, missing woman Holly Grim.

In a press conference on Thursday morning, investigators outlined what led them to charge Horvath with criminal homicide, tampering with evidence, impeding the police investigation into her disappearance, abuse of a corpse and kidnapping.

According to the criminal affidavit, investigators first responded to Grim's home at the Red Maple Acres Mobile Home Park in Lower Macungie Township on November 22, 2013 after Grim's mother, Jeanette, called police.

Jeanette Grim said she tried to call her daughter, like she usually did ever morning. However, after three attempts to get a hold of Holly she went to the home to check on her. Jeanette Grim said she saw Holly's vehicle in the driveway and that the door to the home was unlocked. Inside, she found a spilled coffee mug, overturned ashtray, Holly's asthma medicine and cigarettes which she thought was unusual since Holly was known to take them with her. Grim's mother was not able to locate Holly's cell phone either.

According to the criminal affidavit, Jeanette Grim contacted Allen Organ and learned Holly had not shown up to work and said there was no legitimate reason for her not to. Pennsylvania State Police investigators found Holly Grim's keys on the living room floor and her eyeglasses in the living room. The family noticed the rear door of the trailer was unlocked and realized it was used seldom and kept locked.

A neighbor interviewed by investigators said she saw Grim at the bus stop after she dropped off her son. The neighbor told investigators when Grim came back home, it appeared as if Grim heard something to startle her and look toward the rear of her trailer. Minutes later, the woman told police she heard a loud "thump" come from the direction of Grim's home, according to the criminal affidavit.

Investigators checked with AT&T to look into the whereabouts of Grim's phone and reports showed that Grim's phone was powered on in the morning and received the calls from Grim's mother. The calls hit off of three separate cell phone towers and suggested to investigators the victim's cell phone was moving away from her home that morning, according to the criminal affidavit.

Horvath's charging documents show a forensic investigator was brought into examine Grim's home where it a human blood stain was discovered on the morning she disappeared.

On December 12, 2013, Horvath was interviewed by investigators at his home after police discovered he was one of several employees who were marked as absent or showed up late to work at Allen Organ on the morning of the Grim's disappearance. According to police, Grim and Horvath worked together in the same department at the Macungie-based company.

During that interview, Horvath told investigators he was late to work that morning because he got a flat tire on the way to work and made a temporary repair to repair the tire in South Whitehall Township, Lehigh County about three miles away from Grim's home. Horvath told police he drove back to his home and then drove back to work, according to the criminal affidavit.

Horvath was re-interviewed in June 2014 by investigators and told them he worked for Allen Organ Company for almost 21 years and knew Grim for seven of those years. By that time, Horvath was no longer employed with the company having resigned months after Grim's disappearance.

Horvath told investigators he did not know Grim well but was aware of her usual bowling on Thursday nights, according to the charging documents. The documents also state that Horvath told police he was at Grim's home twice before to assist with moving a washer and dryer in the home through the rear door. Horvath said he was not injured while moving the appliances and allowed investigators to swab his mouth in order to obtain the DNA sample for comparison to the bloodstain found at Grim's door on the day of her disappearance. The DNA matched, according to police.

Two months later, investigators interviewed Horvath's wife, Cathy, who said on the day of Grim's disappearance she knew found her husband's dirty shoes in the bedroom and the bedroom light still turned on, according to the charging documents. She told investigators Horvath had come home that morning because of a flat tire. She said her husband normally disposes their household waste on their property and when he hunts, he disposes of the animals in the woods around their home for other animals to consume.

According to the criminal affidavit, Cathy Horvath also told investigators of her suspicions of her husband having an affair with a female and received a copy of the phone records. Those phone records show how Michael Horvath made a phone call to the woman the morning of Grim's disappearance and a call into Allen Organ Company.

In December, investigators interviewed the woman to confirm she met Horvath on an adult dating website sometime between July and November 2013, according to charging documents. The woman told investigators she met Horvath once but was disturbed by comments he made about following her and her boyfriend around a mall after the woman said she could no longer go on a lunch with Horvath.

On April 20th, investigators again interviewed Horvath only at the Pennsylvania State Police Beffast station where he acknowledged correspondence and a relationship between the woman online, according to the criminal documents. Horvath also acknowledged a phone call to Allen Organ Company on the day of Grim's disappearance to say he was going to be late for work. Investigators also questioned his chosen commute to work on November 22nd, 2013.

Investigators said they had sufficient evidence to believe Grim was held against her will based on their investigation.

On September 27th, a search warrant was executed on Horvath's home where a forensic pathologist identified human bones found buried in the backyard of Horvath's property. On September 29th, a second search warrant was executed on the property where items such as video tapes, DVD's relate to murder, sexual deviance and "hunting humans", according to the criminal complaint. Police also recovered handcuffs, leg shackles, sex toys, and pornographic materials.

A day before the first search warrant on Horvath's home, he was formally arraigned in Lehigh County on a DUI charged stemming from an incident on May 2015.

Horvath was arrested early on Thursday morning at his home in Monroe County. He remains behind bars without bail.