Cullen was arrested on suspicion of kidnapping as the search continued for the little boy. Suspicion grew throughout the day that little Clifford had been murdered, and about 5:00 p.m. searchers decided to drag a pond and search an old well near the Shaw residence. Tracks in the snow leading from the well to the residence and footprints in the mud around the well that matched Richard Cullen's boots further fastened suspicion on Cullen, and after a few casts into the stagnant water of the well with a grabbing hook, the body of the little boy, dressed in his night clothes, was brought to the surface. Investigators almost immediately concluded that they were looking at a case of premediated murder. A heavy car link (used to hook railroad cars together) was wired to the child's neck, and physicians examined the body and found no bruises or wounds, indicating that the boy was thrown into the well while still alive.
The county coroner, who was among the searching party, had the body taken to the courthouse, where he impanelled a jury. The inquest began that very evening and continued the next day. Among the witnesses interviewed was Sarah Shaw, Richard Cullen's mother. She testified that she put the little boy to bed about 8 p.m. on the night of the 22nd in the room where both he and Richard usually slept. She said Richard came home from uptown about 11 p.m., went into his room, and then came into her room and told her Clifford was missing. She got up to check, confirmed that the child was missing, and then went back to bed. At the conclusion of the inquest, Richard was charged with murder, and his mother was charged as an accomplice, because of the indifference she'd exhibited during the inquest.
On the night of February 26, about 150 quiet and determined men gathered on the west side of the Marshfield square about 9:15 p.m. The mob, armed with firearms and sledgehammers, soon marched to the jail and demanded the keys to Cullen's cell. Sheriff John Wesley Hubbard and his deputies put up a token resistance, but realizing that a stout stand would likely result in loss of lives, including their own, they soon handed over the keys. The mob went upstairs to Cullen's cell, where they found the prisoner in his underwear. They bound his hands, put a rope around his neck, and went back downstairs leading Cullen by the rope.
Did he have anything else to say, the leader of the mob asked. "Pull your damn rope," Cullen replied.
"Enough!" the mob leader announced. "Pull away, boys!"
About twenty hands took hold of the rope and pulled, and "Dick Cullen's soul passed into eternity," according to a contemporaneous newspaper account. The body was left hanging as the mob departed, but, at the coroner's direction, it was cut down at 11:00 p.m., about an hour after Cullen was strung up.
Rolla Herald, March 3, 1892, Sedalia Weekly Bazoo, March 1, 1892, History of Webster County by Floy Watters George.