A Texas man missing for weeks was actually dead and had been totally consumed by his pack of aggressive dogs, officials said Wednesday.

The family of Freddie Mack, 57, told the Johnson County Sheriff's Office in early May that he hadn't been seen or heard from in about three weeks, authorities said.

"During the course of our investigation it was found that Freddie suffered from serious medical conditions, so we will never know if the dogs killed Mr. Mack or consumed him after he died from a medical condition," Johnson County Sheriff Adam King told reporters. "Either way, it is a very gruesome event and we extend our sympathy to Freddie Mack’s family."

Freddie Mack Johnson County Sheriff's Office

When deputies first searched Mack's 3 1/2-acre property in Venus, Texas, about 30 miles south of Dallas, all they found were more than a dozen aggressive dogs and no signs of the missing man, officials said.

Deputies made multiple trips to Mack's property before a detective, on May 15, found a small bone.

"There was something about it that stood out to her," Deputy Aaron Pitts said of that single bone fragment.

A forensic anthropologist told investigators the bone was human and follow-up searches turned up more bones. Investigators also found dog feces that appeared to include human hair and bits of clothes that matched what Mack normally wore, according to Pitts.

Samples of DNA from Mack's family matched genetic material on bones found on the man's property.

There had been 18 dogs living with Mack, but two were found dead, having been killed by their fellow canines, Pitts said.

Thirteen dogs had to be put down because of poor health or their aggressive nature that made them impossible to be adopted. That leaves three dogs that officials said are healthy and being prepared for adoption.

"I am a dog lover and have three of my own. When we're starving, we make decisions we normally wouldn't make," Pitts told NBC News. "Animals do what animals need to do, which is to survive. I still certainly consider dogs to be our best friends."