Investigators say an injured woman acknowledged inventing the robbery account to shield the son now accused of attacking both parents.
TUCSON, Ariz. — The first story Pima County sheriff’s deputies heard involved two masked robbers. The account soon changed, leading detectives to accuse the couple’s 39-year-old son of an assault that left his father dead and his mother hospitalized.
That change is central to the criminal case against Tyler Lachmann. According to an interim complaint cited by Arizona news organizations, Lachmann’s 72-year-old mother initially told investigators that masked men had entered the family home, robbed her and her husband, and injured them. In a follow-up interview, she allegedly said the intruders did not exist and that she had given the account to protect her son. Detectives then reconstructed what they described as an unprovoked attack by Lachmann against both parents during the night of June 28.
The investigation began as something less clearly criminal. Deputies were dispatched shortly before 12:30 p.m. June 29 to a residence near Oracle and Hardy roads after a possible cardiac arrest was reported. Inside the home, they found 73-year-old Chris Lachmann dead. His wife was alive but injured and later taken to a hospital. Sheriff’s officials said both parents had wounds consistent with a violent assault, immediately raising questions that a cardiac-arrest report alone could not answer.
The alleged robbery account offered one possible explanation. According to the complaint, the surviving woman said two masked men were responsible. Such a report would have directed investigators toward unknown outsiders who had entered the residence, attacked the occupants and fled. The public reporting does not say whether she described stolen property, a point of entry or weapons carried by the supposed intruders. It also does not say whether detectives found signs of forced entry or missing belongings. Authorities have not released a full evidence inventory from the house.
Investigators conducted another interview, and the account shifted. The woman said she had lied to protect her son, the complaint alleges. Her revised statement identified Tyler Lachmann as the person who attacked both parents. Authorities have not disclosed the exact wording of the questions asked during the interviews, whether the woman had an attorney present or how much time passed before she changed her statement. The complaint’s account is the prosecution’s version of the investigation, not a finding by a jury.
Under the revised chronology, the violence began the previous night. The mother said Tyler Lachmann repeatedly punched her and slammed her head against concrete, according to the filing. She alleged that he then attacked his father while the three were in the kitchen. The complaint characterized the violence as occurring “without provocation,” but it did not identify a triggering dispute, describe a demand or state that the father and son had argued beforehand. The absence of a publicly stated motive remains one of the case’s major unanswered questions.
The mother’s actions after the alleged assault add another unresolved part of the timeline. The complaint says she helped her injured husband into bed, removed his shirt and changed him into sweatpants. She checked on him during the night before going to sleep, investigators allege. By morning, she said, he had stopped breathing and felt cold. The filing does not explain why emergency help was not summoned sooner, whether the mother’s own injuries impaired her judgment or whether she believed her husband was merely sleeping and would recover.
Those unanswered questions do not by themselves show wrongdoing by the surviving woman. A person who has just experienced violence may be injured, disoriented, frightened or focused on immediate survival. The available court account does not include a medical evaluation of her condition during the night. Authorities also have not announced that she was arrested or accused of failing to obtain care. The only conduct attributed to her in the complaint beyond the events in the home is the initial false description of masked robbers.
The case then moved rapidly from conflicting witness accounts to an arrest. Sheriff’s homicide detectives identified Tyler Lachmann as the suspect, and the department’s Fugitive Investigations Unit began looking for him. Officers found him later June 29 near Grant Road and Interstate 10. Public reports do not describe a chase or confrontation during the arrest. He was booked into the Pima County Adult Detention Complex on allegations of first-degree murder and domestic-violence vulnerable adult abuse.
Investigators have not publicly described what Lachmann said after his arrest. The reviewed reports do not indicate whether he agreed to an interview, denied the allegations, invoked his right to remain silent or provided an alternative account. No defense statement addressing the mother’s allegations was identified in the available coverage. Without that information, the public version of events rests primarily on the surviving woman’s revised statement, the injuries deputies observed and the conclusions outlined in the complaint.
Physical and medical evidence could become important as the case proceeds. Investigators will need to establish how Chris Lachmann died and connect that death to the alleged assault. Initial reports said the injuries on both parents were consistent with an attack, but they did not provide a final autopsy finding or specify whether the father died from head trauma, other injuries or a medical complication. A charging decision can be based on probable cause, a lower standard than the proof beyond a reasonable doubt required for a conviction.
The changing account may also receive close attention in later court proceedings. Prosecutors could argue that the mother’s admission explains why investigators initially received inaccurate information. A defense lawyer could examine the conditions under which both statements were given, including her injuries, memory and mental state. The fact that a witness changes an account does not automatically make the later version true or false. Courts generally evaluate statements alongside medical records, physical evidence, recorded interviews and testimony from responding officers.
Authorities said the accused man had been on pretrial release in an unrelated felony case. Reporting on the interim complaint said he was previously accused of pointing a gun at his girlfriend’s mother and threatening to kill her during an April 29 encounter. The earlier allegation was not adjudicated in the sources reviewed for this article. It remains legally separate from the accusations involving his parents, even if prosecutors raise his release status during arguments about detention or conditions of release.
The mother also reportedly told prosecutors that her son had mental health problems. No diagnosis, treatment record or professional assessment was included in the publicly described complaint. The statement may help explain why she believed she needed to protect him, but that would be an inference rather than an established fact. The public record reviewed here does not establish why she first blamed masked attackers, why she later changed her account or how she understood her son’s condition at the time.
Initial reports said Lachmann was held without bond and was expected to appear at a bond hearing July 6 and a preliminary hearing July 10. Reliable public information reviewed for this update did not confirm the results of those scheduled proceedings. Arizona’s online case-access system also cautions that its information may not always be complete or current and is not a substitute for the official court record.
Several major facts therefore remain open: the final cause of death, the reason for the alleged attack, Lachmann’s response to the accusations and the present procedural posture of the prosecution. What authorities have stated is that a call first presented as a medical emergency and a robbery report became a homicide case involving members of one family. Lachmann is presumed innocent unless proved guilty.
Author note: Last updated July 28, 2026.