At around 5 p.m. on November 28, 2002—Thanksgiving Day—44-year-old Timothy Mammen, a methamphetamine dealer, was found fatally shot four times in the back of the head on the second floor of his home in Plymouth, Iowa. An autopsy indicated that he had been shot several hours earlier and friends of Mammen told police they had been at the home until about 1 a.m. and that Mammen was still alive.
Mammen’s girlfriend, Courtney Askvig, told police that Mammen had called her before midnight and mentioned that 33-year-old Eric Esse was among those present. Police located Esse in his home in Albert Lea, Minnesota, about 40 miles north of Plymouth, and interrogated him for more than eight hours over two days.
At first, Esse denied being at Mammen’s house, but over the course of the interrogation, he gave gradually shifting responses, saying that he had gone there to buy drugs and had consumed some on the premises. According to an audio recording of the interrogation, Esse first modified his denial to say he was in the yard when he heard the shots fired. Then he said he was at the bottom of the stairs to the second floor and later, he said he was in the room when someone else shot Mammen. At one point, Esse said he left Mammen’s house when Mammen was still alive, but returned in the early afternoon on Thanksgiving Day and found Mammen dead. He said he stole some of Mammen’s money and left. In the final portion of the interrogation, Esse denied all involvement in the shooting. He told the investigators he had been telling them what he thought they wanted to hear.
When police said some of his statements contained information only the killer would know, Esse implicated another man, Scott Peterson and said that Peterson had told him about the shooting in a telephone call two days after Mammen was killed. Peterson later denied any involvement in the crime.
Esse was arrested and charged with first degree murder and robbery. Investigators subsequently learned that Esse had borrowed a pistol from a friend at about the time of the murder. The friend, who gave the gun to police, said Esse told him he needed a gun to shoot a raccoon that was harassing his mother’s apartment.
Esse went on trial in Cerro Gordo County District Court. A ballistics analyst testified for the prosecution that although the bullets recovered from Mammen’s head were mangled, the striations on the bullets were consistent with the rifling of the barrel of the pistol that Esse had borrowed from his friend. Esse’s friend told police that when Esse returned the revolver, there were six spent cartridges in the cylinder.
Prosecutors aired the audio tapes of Esse’s interrogation for the jury. Esse’s wife testified that she was using the family’s only functioning vehicle on Thanksgiving afternoon and that Esse could not have been in Plymouth discovering the body as police said he admitted doing.
On October 17, 2003, a jury convicted Esse of murder and robbery. He was sentenced to life in prison without parole. In September 2005, the Iowa Court of Appeals reversed the conviction, ruling that the trial judge had erred when he refused a defense request to instruct the jury that only Esse’s statements during the interrogation—and not the comments of the detectives who were questioning him—should be considered as evidence. “The interviews…contain several statements that, if viewed as evidence, indicate Esse was lying or the agents had unspecified evidence of Esse’s involvement beyond that which was introduced at trial,” the appeals court said. “For example, the agents repeatedly stated that there was 'no doubt' Esse was involved in the murder.”
In 2006, Esse went on trial a second time in Bremer County District Court after a motion for a change of venue was granted. A new defense attorney, David Staudt, the Chief Public Defender in the Iowa State Public Defender's Office, presented the testimony of a ballistics expert who said that his analysis ruled out the borrowed pistol as the murder weapon. In addition, Staudt presented an expert on false confessions who testified that Esse had been overborne by the lengthy interrogation and had made statements he believed the detectives wanted to hear. Esse testified in his own behalf and denied involvement in the murder. On December 15, 2006, a jury acquitted Esse and he was released.
– Maurice Possley
The National Registry of Exonerations is a project of the Newkirk Center for Science & Society at University of California Irvine, the University of Michigan Law School and Michigan State University College of Law. It was founded in 2012 in conjunction with the Center on Wrongful Convictions at Northwestern University School of Law. The Registry provides detailed information about every known exoneration in the United States since 1989—cases in which a person was wrongly convicted of a crime and later cleared of all the charges based on new evidence of innocence.
We welcome new information from any source about exonerations already on our list and about cases not in the Registry that might be exonerations.