Here's what we know about the series of events involving patients at Christus Mother Frances Louis and Peaches Owen Heart Hospital that led to the arrest of a former nurse, William George Davis, who was charged with murder in the death of a patient at the hospital.
June 22, 2017: A 61-year-old male patient experiences a profound and unexplainable incident resembling stroke-like symptoms.
July 14, 2017: A 58-year-old male patient suffers a significant injury from a profound and unexplainable incident resembling stroke-like symptoms.
Aug. 2, 2017: Christopher Greenaway, 47, of Tyler, is admitted to the heart hospital.
Aug. 3, 2017: Greenaway has a coronary artery bypass graft surgery. He was neurologically intact after his surgery and taken to the intensive care unit of the hospital. He was extubated shortly after 4:30 p.m. and was breathing well on his own.
Aug. 4, 2017: Greenaway's assigned nurse checks on him about 3 a.m. and believes he is stable. The assigned nurse asks nurse William George Davis to watch Greenaway while he goes to get something to eat. The assigned nurse returns to the hospital and hears the code sounding for Greenaway's room. Greenaway suffers an unexpected neurological incident shortly after 3:35 a.m.
Aug. 6, 2017: A brain death evaluation is conducted and Greenaway is declared brain dead on the evening of Aug. 6 and dies. Greenaway's organs and tissues are subsequently donated.
Aug. 7, 2017: A 54-year-old male patient suffers a significant injury from a profound and unexplainable incident resembling stroke-like symptoms.
Oct. 26, 2017: A 56-year-old male patient suffers a significant injury from a profound and unexplainable incident resembling stroke-like symptoms.
Nov. 30, 2017: Pamela Henderson, 64, of Tyler has heart surgery at the hospital. She came out of surgery with no significant complications and was transferred to the intensive care unit. Shortly after midnight on the next day, Henderson experiences an unexpected profound neurological event.
Security camera footage shows Davis entering Henderson's room. He was in Henderson's room when her primary nurse entered the room and found the pressure was too high on her arterial line. Doctors notice air in her brain on a CT image. Henderson has limited mobility and visual problems as a result of her stroke-like injuries, according to the arrest affidavit.
Jan. 24, 2018: Joseph Kalina, 58, has heart bypass surgery at the hospital. Kalina is transferred to the Cardiovascular Intensive Care Unit where nurse William George Davis was assigned.
Jan. 25, 2018: A nurse speaks with Davis about an abnormality on Kalina's arterial line waveform. Davis initially tells the nurse he went into the room to reset a pump alarm that showed an "upstream occlusion" in the Baxter IV pump. This statement was later determined to be untruthful. Security camera footage shows Davis in Kalina's room for about one minute, though Kalina is not one of his assigned patients. Three minutes later, Kalina suffered a profound medical neurological emergency. Christus Mother Frances Hospital-Tyler removes Davis from patient care.
Jan. 28, 2018: Davis contacts the nurse who spoke with him about the abnormality and tells her he flushed Kalina's arterial line multiple times.
Jan. 28, 2018: Christus Mother Frances Hospital - Tyler meet with authorities on regarding situation with Nurse Davis.
Feb. 8, 2018: Tyler Police Department investigators attend a meeting with hospital staff and counsel where they learn of a series of patients who suffered unexpected medical emergencies at the Louis and Peaches Owen Heart Hospital while they were recovering from heart surgery.
Feb. 15, 2018: Davis' employment with Christus Mother Frances Hospital-Tyler is terminated for his falsification of care events and his unethical practice related to failure to disclose interventions provided that may have impacted the outcome of a patient.
Feb. 20, 2018: Davis is interviewed by detectives from Tyler Police Department. Davis said he remembered watching Greenaway while his nurse went to eat.
March 6, 2018: Tyler police investigators meet with a doctor retained by the Smith County District Attorney's Office to assist with the case. Investigators said the doctor believed air was found to have been deliberately introduced into the arterial circulation using the patient's arterial lines.
March 8, 2018: Tyler police meet with the chief forensic pathologist at Forensic Medical of Texas to discuss the case.
March 16, 2018: The Texas Board of Nursing holds a public meeting to consider the suspension of Davis' nursing license. Texas Board of Nursing staff present information and evidence about his conduct and whether "his continued practice as a nurse would constitute a continuing and imminent threat to the public welfare." Davis' nursing license is suspended.
March 22, 2018: Tyler police meet with a board-certified radiologist at his office in Dallas. The doctor told investigators the neurological emergencies in the cases were not accidental.
March 27, 2018: Investigators receive a report from the chief forensic pathologist at Forensic Medical of Texas. In it, the doctor states, "The cause of death of Christopher Greenaway is cerebral ischemia due to an induced air embolus. The manner of death is homicide."
April 2, 2018: Investigators receive a report from the Dallas-based radiologist. In it, he concludes, "The actions of nurse Davis led to the death of Mr. Greenaway and the permanent injuries suffered by Ms. Henderson and Mr. Kalina."
April 10, 2018: Tyler police call Davis and ask him to come to the police station. Davis is arrested and charged with the murder of Greenaway.
April 11, 2018: Tyler Police Department holds a press conference to tell the public about the arrest and investigation.
April 13, 2018: Crosley Law Firm in San Antonio files medical negligence claim against Christus Mother Frances Hospital seeking damages for Joseph Kalina.
Sources: Tyler Police Department, arrest warrant affidavit and Texas Board of Nursing website