OKLAHOMA CITY - A violent offender is locked up again after investigators said he had possession of over 100 images of child pornography. 

Oklahoma Attorney General Mike Hunter reports the circumstances around this crime are very disturbing.

“Clearly this individual is someone who has involved himself in something that is victimizing helpless children,” said AG Hunter.

This case took over a year to investigate and was backed by the state's multi-county grand jury.

After getting a tip from the National Center for Missing & Exploited Children, state investigators said they began looking into a single IP address. It was allegedly connected to sites like "CommunityIncest.com" and the username: "taboofeet." Images depicted children "five and 11 years old" performing acts on "adult men..." and were tied to a separate “photobucket” account.

Investigators continued down the digital trail and found a suspect by the name of David McKissick.

McKissick is no stranger to prison. He’s been previously convicted of burglary, arson and drug crimes.

Police in Little Elm, Texas said McKissick also allegedly "engaged in sexual contact with a 12-year-old..." when he was 17.

By January 2019, police traced the IP address to a home in Oklahoma City, where they searched and found more evidence. They said they found a video of a person touching themselves to child porn on a personal laptop, and a voice that said, "This is why you shouldn't let me babysit by four-year-old cousin."

Also, pictures of "children's feet" were found on a device.

“We have no sympathy, nor do we view this as anything other than a crime that we have to deal with through a zero-tolerance approach,” said AG Hunter.

The home listed in the search warrant allegedly belonged to family of McKissick.

According to court documents, family said McKissick has been to mental health facilities more than 25 times.

The owner of the home was sick throughout 2018 and had been hospitalized for months.

When McKissick was at the property alone, witnesses said he let "several people live there...," who were possibly homeless, and many items inside were stolen.

The suspect was already in jail when investigators finally tracked him down. He declined to be interviewed without an attorney.

McKissick will be in Cleveland County court in a few weeks.