As strange as the tale of Michael Timothy Cavanaugh had been, the case became even more bizarre once he was arrested. After several days of denying that he knew ex-Marine Ralph Welch, even though he was driving Welch’s car and had Welch’s wallet and ID papers, Cavanaugh agreed to be interrogated under the influence of sodium amytal, often referred to at the time as “truth serum.”
In the days that followed, Cavanaugh gave several conflicting accounts of killing Welch, but the information he provided enabled Albuquerque police to locate Welch’s remains off Route 66. Desert animals had eaten much of the body, which was badly decomposed, making it impossible to determine the cause of death.
Later that month, Cavanaugh was returned to California on charges of passing bad checks. In October, he was again questioned under the influence of sodium amytal, but the psychiatrist who questioned him said that Cavanaugh was faking his answers.
Cavanaugh went on trial for passing fraudulent checks in November 1953. During his trial, Cavanaugh asked to make a statement in court and said that he killed Welch on July 23, 1953, in Tijuana “as an aftermath of an argument resulting from a drunken orgy.”
Among his Cavanaugh’s various versions of what occurred was the claim that he and Welch drove to Tijuana, where they picked up two girls. Cavanaugh said he left to buy food and when he returned to the car, he found Welch “sexually mistreating” Cavanaugh’s female companion.
Cavanaugh claimed that he killed Welch, put the body in the trunk and drove back to Chula Vista.
A jailhouse informant named Patrick O’Riley admitted helping Cavanaugh concoct a confession that he killed Welch in Tijuana under the assumption that he would receive a lighter sentence if he were tried in Mexico. Investigation by Mexican authorities, however, disproved Cavanaugh’s contention that the killing had taken place there.
In April 1954, Cavanaugh was found guilty of first-degree murder and a plea of insanity was rejected. In 1956, the U.S. Supreme Court rejected Cavanaugh’s appeal in which he claimed that the killing occurred in Mexico.
Michael Timothy Cavanaugh was executed in the gas chamber April 13, 1956.