After killing Becky, Lucas’s first instinct was to run, to get away from the one crime that continually preyed on his mind. He claimed that he was tormented by Becky’s "voice from the grave," but two things stopped him from leaving. The first was disposing of the body, the second, and most important, was to build a suitable alibi for himself. Anxious to cover his tracks, he decided to return to the "House of Prayer." Two days later, Lucas walked on to the ranch and went to see Reverend Moore. When Moore asked about Becky, Henry broke down in tears and told him that Becky had run off with a truck driver while they were hitchhiking. He asked if he could stay and work at the ranch for a while until he got himself sorted out. Moore agreed and Lucas settled back into his usual daily routine. Two weeks later, he returned to the murder scene to bury Becky’s remains. He told police, that when he returned to the site he was so overcome with grief that he could only bury half of her.

It is not known if Henry’s feelings of guilt and remorse were real or not, but one thing is certain. After killing Becky, something inside him obviously changed. He become less cocky and attentive to details, a fact that would eventually bring about his downfall.

In the small community of Stoneburg, word quickly spread of Henry’s return, minus Becky. One person who was more concerned than the rest was Kate Rich. Hearing that Henry was back at the ranch, she contacted him and asked about Becky. Henry told her that he would come and talk to her about it and offered to drive her to her regular evening church service. Kate agreed and the date was set.

On the appointed day, Henry arrived early driving Moore’s car. After picking up Rich, he drove into Oklahoma to pick up some beer. They began discussing Becky and Rich pushed him for more details, stating that she didn’t believe that Becky would have done such a thing. Lucas started to get angry at the insistent questioning. By the time they had driven back from town, it was too late for church so Lucas suggested that he drive her home.

Kate Rich continued to badger Lucas for answers until, finally he’d had enough. Pulling off on a deserted road, he pulled his knife and plunged it into Rich. After she collapsed, he took her body from the car and after carving an inverted cross in her chest, had sex with her corpse and dumped her in a culvert.

After returning to the ranch, Moore asked Lucas about the church service. Henry told him that when he went to pick up Rich, she had decided not to go because she was feeling sick. Moore, knowing that Rich was in poor health, accepted the story.

Later that night, Lucas took several garbage bags from the kitchen and drove to where he had dumped the body. After carving her remains into small pieces and packing them into the bags, he returned to the ranch.

Lucas stayed up most of the night, burning the body parts in the wood stove in the compound's kitchen. It was 5 a.m. before he was satisfied that his victim would not be found, still early enough to leave the ranch undetected. Before sunrise, Henry had taken Moore’s car and headed north to the border. He knew that he had to put some distance between himself and his latest victim, as Moore was sure to tell anyone who asked, that Lucas was the last person to see Kate Rich alive.

The following Monday, Rich’s relatives tried in vain to contact her. Worried about her health, they decide to drive to her home to investigate. After making inquiries, they became suspicious and rang the local sheriff, Bill "Hound Dog" Conway, who filed a missing persons report. The relatives told Conway about Lucas and how he had stolen money from the old woman previously. The trail led to the "House of Prayer" where Moore confirmed that Rich was last seen with Henry Lucas.

Conway returned to his office and ran a criminal records check on Lucas. When he found that Lucas not only had a previous history of rape and murder, but also had outstanding warrants for parole violations, he circulated an arrest order. Unfortunately, by that time, Lucas had already left Conway’s jurisdiction.